Overview
     
The Skill Scaling Patch fixes a number of bugs or inconsistencies in character skills, mostly about the way they scale with level, and across playthroughs. It is not meant to change the balance of the game according to my personal preferences, but to make it work as intended (or at least more consistently), which does improve some aspects of the balance. The skills that are the most affected are Phaselock and Ruin (Maya), Light the Fuse (Krieg), Deathtrap and all its damage abilities (Gaige), the Sabre Turret and all its damage abilities (Axton), Salvador (Steady as She Goes).
   
Concerning Deathtrap and the Sabre Turret, the main problem addressed by this patch was actually not present on console. With the Skill Scaling Patch, their damage output should thus be identical to what it is on console. And that makes a huge difference on their end-game viability.

I have also added some fixes to balance inconsistencies resulting from the level cap increase (80+OP10). And an optional (balanced) boost to status effect damage in UVHM and OP levels.
   
Installation and Compatibility
   
Use BLCMM to install the Skill Scaling Patch:

• Install BLCMM
• In BLCMM > Tools > Setup game files for mods: enable the Mod support options, and any other you may want. 
• (Since the recent UHD update, the previous step will only work on linux. On PC, you have to use another method to hexedit. Grab Cody's Hex Multitool. You can also check out this video, for example. On mac you need to hexedit manually).
• Open SkillScalingPatch.blcm in BLCMM (or use File > Import Single mod, if you want to combine it with other mods)
• In BLCMM > File > Save as: select "Open BL2 Binaries Dir", and save it under any name you like. Since some recent changes in the hotfix system, you may need to check the "Offline" option in BLCMM before saving (doesn't affect co-op).
• Launch your game. In the menu with New Game, Character selection, etc, press "Esc" to exit to the main menu.
• Open the console (using the key you selected when setting up your game files for mods in BLCMM), and type e.g. "exec SkillScalingPatch.blcm".
• Close the console, press key to continue, and you're good to go.
  

The Skill Scaling Patch can be used as a standalone, for a vanilla experience with less bugs, and to meet Deathtrap and the Sabre Turret the way they were supposed to be (and actually are, on console). You can also try to combine it with other mods, using BLCMM. However, this may create incompatibilities if the other mods affect the skills modified by the Skill Scaling Patch, or even skills in general. I'd recommend importing the Skill Scaling Patch after other mods, and disabling any changes affecting the mentioned skills, in those other mods.
   
Some parts of the Skill Scaling Patch have been included in the Unofficial Community Patch (version 4.1 and later). However, some parts are not, or may be in a somewhat outdated version, so you may still want to add the Skill Scaling Patch on top of the UCP. It should be fully compatible, as long as you import the Skill Scaling Patch as a single mod after the UCP (do not open the Skill Scaling Patch, then import the UCP).

If for some reason you still have a level cap at 72 + OP8 (linux maybe? I'm not sure), use the version 2.6 of this mod.
   
Detailed changes
   
You can find here all the damage values at different levels/playthroughs, on console and on PC/mac (with or without the Skill Scaling Patch). This website is not fully updated after the level cap increase.
    
The % bonuses given below are multiplicative with other bonuses you may get in-game (e.g. +160% means that whatever damage you were doing should be multiplied by 2.6). The values are given at specific levels as examples, but they evolve continuously with character level.
    

General

General Skill damage scaling.

• Make Ruin damage (elemental explosions and DOTs) scale like other skills, and remove the level 80 cap.
• This also affects the status effect damage from a few other skills (Blight Phoenix, Cloud Kill, Unf0rseen)
• Damage increase of +60% at level 30, +100% at level 50, +160% at 80, +850% at OP10.
  

Adapt UVHM-OP balance modifiers to the new level cap.

• Move the balance modifiers specific for OP levels to 81+ instead of 73+, to account for the new level cap.
• This does not affect the difficulty in OP levels, but removes inconsistencies in the 73-80 level range.
• The 73-80 level range is made to be intermediate between 61-72 and OP levels, in terms of enemy health regen and white/green gear drop rates. (In the current vanilla: enemy health regen in 73-80 is as fast as in the OP levels. With this patch it's decreased, but not as low as in the 61-72 range. The effect on drop rates is very minor and does not affect unique drops at all). 
  

Axton
  
Sabre Turret: made its damage scale the way it was supposed to (and actually does, on console).

• This affects the damage of the bullets, the Scorched Earth Rockets, Nuke, and the capacity of the Phalanx Shield.
• Bullets, Rockets & part of the Nuke damage: -43% damage at level 5 (Normal), -17% at level 30 (Normal), +34% at level 30 (TVHM), +68% at level 50 (TVHM), +118% at level 80 (UVHM), +135% at OP10.
• Other part of the Nuke damage: +4% at level 30 (Normal), +110% at level 50 (TVHM), +173% at level 80 (UVHM), +194% at OP10.
• The Sabre Turret gets a bonus to its damage in co-op. The max bonus (4 players) should be about x1.9 in Normal, and about x1.3 in TVHM/UVHM.
• All of this should now be exactly the same as it is on console.
• In addition, the Fire DOT from Nuke had a damag cap at level 80, and did not scale into the OP levels (also a problem on console). This cap was removed,  leading to an increase in damage of more than 900% at OP10.
• In addition, the Phalanx Shield capacity is made to scale better, to stay roughly constant relative to the turret's health. This is not the case on console.    
  

       
Gaige
   
Deathtrap: made its damage scale the way it was supposed to (and actually does, on console)

• This affects the base melee damage, and the damage from its skills (Explosive Clap, The Stare, etc)
• Damage decrease of -29% at level 5 (Normal), increase of +4% at level 30 (Normal), +110% at level 50 (TVHM), +173% at level 80 (UVHM), +194% at OP10 .
• The multiplicative bonus on his roid damage from Sharing is Caring now depends on level: instead of a constant value of x1.4, it increases from about x1.5 at level 31 (Normal), to about x4.1 at OP10.
  

• Deathtrap now gets a bonus to his damage in co-op. The max bonus (4 players) should be about x1.9 in Normal, and about x1.3 in TVHM/UVHM.
• All of this should now be exactly the same as it is on console.
  

   
Deathtrap: fixed a bug that made the interaction between Make it Sparkle and Sharing is Caring (with a roid shield) completely broken.
   
Made of Sterner Stuff: fixed a bug that gave Gaige too much damage reduction against Burn status effect.
   
Electrical Burn: compensate for the double dip in damage penalty against higher level enemies in the OP levels (the special mechanics of this skill made it so that it was doing only about 12% damage versus a level 80 enemy, while other skills and weapons are doing 35% damage).   

• No effect up to level 80. Damage increase in the OP levels, up to +186% at OP10.
  

   
Krieg
   
Light the Fuse: removed the level 80 cap.

• No effect on damage up to level 80. Damage increase in the OP levels, up to +266% at OP10.
  

   
Krieg's innate melee damage bonus (without blade attachment): removed the level 80 cap.

• No effect on damage up to level 80. Base melee damage increased by +7.7% at OP10.
  

       
Maya
   
Ruin (elemental explosions and DOTs): made to scale like other skills and removed the level 80 cap (see above).    
   
Phaselock damage on non-phaselockable targets: made to scale like other skills.   

• Damage increase of +60% at level 30, +100% at level 50, +160% at 80, +180% at OP10
  

    
Scorn: made to scale like other skills.   

• Damage increase of +60% at level 30, +100% at level 50, +160% at 80, +180% at OP10
  

   
Immolate: compensate for the double dip in damage penalty against higher level enemies in the OP levels (the special mechanics of this skill made it so that it was doing only about 12% damage versus a level 90 enemy, while other skills and weapons are doing 35% damage).   

• No effect up to level 80. Damage increase in the OP levels, up to +186% at OP10. 
  

    
Salvador
   
Gunzerking: fix the recoil reduction with Hyperion weapons  

• Salvador gets a bonus on recoil reduction while gunzerking, but this was not working properly with Hyperion's reverse recoil.
  

    
Steady as She Goes: fix the effect of this skill on Hyperion weapons.

• The passive 80% recoil reduction (while gunzerking) becomes an accelerated reverse recoil for Hyperion weapons.
• The chance to improve accuracy on both guns now actually increases accuracy of Hyperion weapons instead of decreasing it.
• It still works the same for non-Hyperion weapons, except that the calculation of the amount of accuracy gained is somewhat changed, but in all cases it should be noticeable without being excessive.
  

    

Optionals

General: Boost status effect damage in UVHM/OP levels.

• Some mechanics in UVHM/OP levels tend to hurt status effect damage a bit more than other sources of damage.
• Status effect damage is boosted here by 15% from level 50, 20% from level 61, and 25% from level 72, to compensate for enemy health regeneration.
• In OP levels, status effect damage is boosted by 50% to compensate for enemy health regeneration AND decreased status effect chances resulting from level differences.
• The fix to Gaige's Electrical Burn is adapted so that this skill doesn't end up benefiting twice from these boosts.
  

Maya: Phaselock activates Wreck/Elated/Chain Reaction after hitting immune target.  

• After hitting a non-phaselockable target, Phaselock remains artificially active for the base phaselock duration of 5 seconds (not affected by Suspension).
• During that time, Chain Reaction, Elated, and Wreck are active (if specced into) and give all their bonuses.
• Phaselock cooldown will only start after this phase is finished (even if not specced into Wreck/Elated/Chain Reaction)
• It does not change anything about the way Phaselock works with regular targets.
• When combined with Subsequence, a bug may sometimes happen that will keep Phaselock active for a few additional seconds.
  

   
Maya: Cloud Kill Dynamic Nerf.  

• Cloud Kill is nerfed depending on the playthrough. This is an improved version of my previous mod (which was also included in the UCP).
• Cloud Kill does 15% of its vanilla damage in Normal mode, 25% in TVHM, and 60% in UVHM (from level 50).
• In the OP levels, the damage progressively increases to reach 100% of the vanilla Cloud Kill damage at OP10.
  

     
Gaige: Deathtrap's ranged shock attack (used against flying and non-phaselockable targets) benefit from all his melee damage bonuses.

• This only affects the shock attack Deathtrap uses against flying and non-phaselockable targets.
• It will benefit from all damage bonuses, including Make it Sparkle, and roid damage with Sharing is Caring.
• This makes his damage output more consistent against different types of enemies.
• The animation was modified so that the damage is spread over 2 damage ticks instead of 7 (per shock beam), but the overall damage should be exactly the same in absence of any melee damage bonuses.