This mode has been started for myself and includes some updates just to do the Witcher 1 interface more or less similar to W3.
I designed to share it now. It collected some other TW3 modes to one place plus add some new vision.

The mod content includes:

The update of GUI to do the Witcher1 more similar to TW3 style view. (This update based on RotWW).

Additional icons for mode
TW3 Item Icons for The Witcher https://www.nexusmods.com/witcher/mods/965

Icons of weapon. The steel/silver swords icons from TW3.
Some icons have beem done based on the models from "Complete Sword Overhaul" https://www.nexusmods.com/witcher/mods/719
and
The Witcher Remaster Project sword set https://www.nexusmods.com/witcher/mods/883
New icons for the mode
The Witcher 3 Wolven Sword set https://www.nexusmods.com/witcher/mods/884

TW3 journal images of some charaters (Itsheppard and Hiuuz Witcher 3 charaters).
Additional TW3 images for other characters (more or less similar to Witcher 1).

TW3 images for the bestiary monsters (unfortunally not all).

Small extansionof the TW3 font (Cyrillic font added, dialog font size changed to do it more similar to TW3)
original mode https://www.nexusmods.com/witcher/mods/961

Installation:

UI FILES installation:
Copy "z_zrotww" folder from archive to the same place as original RotWW (actually Data folder of the game).
It will add TW3 folder with some subfolders to RotWW (none impact to the original mode).

PS. I recommend to install RotWW due to the mode does not include everything just some updates.
Please pay attansion: Fixed UI comments ih the game - English.
To uninstall, simple delete TW3 folder or subfolders with unnecessary category of mod.

SWORD ICONS installation:
For "Complete Sword Overhaul" installed
Extract the "TW3_swrd" folder from archive and copy to the folder z_zSwords_DM (main folder of original mode).
Optional
The mode includes and additional icons for "Witcher 3 Wolven Sword set" (each level in separate subfolder, use necessary level if you use it).
Take the files from correponding level folder and moved it to folder "TW3 swrd"(new) inside of "z_zSwords_DM" (confirm to override files "*001").

If you do not use Complete sword Overhaul you can move new sword icons (see above) to "z_zrotww" (insatalled) or "Override" (not Rotww).
The corresonding sword can be used with new UI and original/vanila UI
It looks not quite good, with RotWW, better to use "The Witcher HUD Compilation mode" istead of RotWW.
https://www.nexusmods.com/witcher/mods/990

To uninstall, simple delete TW3_swrd folder from the corresponding place.

FONT installation:
Extract the contents of the downloaded archive to the game directory.
Assuming the game is installed in %ProgramFiles%\The Witcher the full path to the extracted files would be:

%ProgramFiles%\The Witcher\Data\Override\fonts.2da
%ProgramFiles%\The Witcher\Data\Override\fonts_rus.2da
%ProgramFiles%\The Witcher\System\__cache\tw3pfdin_*.fontcache
%ProgramFiles%\The Witcher\System\__cache\tw3pfdinb_*.fontcache

This mod should not overwrite anything in the vanila.
To uninstall, simply delete the files listed above (as a matter of fact, deleting fonts.2da and fonts_rus.2da is enough:
the default version of the file stored inside a BIF archive will be used instead).
If however, for some reason you need the original version of fonts.2da fonts_rus.2da,
for example for your own experimentation, you can also find it in the archive.
To restore the and original version TW3 font.2da and *.fontcache files please use the corresponding mode
https://www.nexusmods.com/witcher/mods/961

Recommended to install:

Witcher 3 charaters. (journal images basically done excatly for the applied characters)
The total list you can see under https://www.nexusmods.com/witcher/mods/categories/38/

RotWW mode https://www.nexusmods.com/witcher/mods/669
Complete Sword Overhaul https://www.nexusmods.com/witcher/mods/719
Witcher 3 Aerondight https://www.nexusmods.com/witcher/mods/923
Geralt of Rivia Face Retexture Witcher 1 https://www.nexusmods.com/witcher/mods/791
The Witcher Overhaul Project https://www.nexusmods.com/witcher/mods/703
Witcher ROTWW menu replacer https://www.nexusmods.com/witcher/mods/856 (main image)

Credits:
Special thanks to:
RotWW team - original concept of updated UI
https://www.nexusmods.com/witcher/users/798828 - TW3 Item Icons Kuczaja
https://www.nexusmods.com/witcher/users/133577168 - The Witcher 3 UI font CloudGiant
https://www.nexusmods.com/witcher/users/3284409 - Wither 3 sound hardkiller
https://www.nexusmods.com/witcher/users/42740305 - Witcher ROTWW menu replacer, TheMightyHazmat
https://www.nexusmods.com/witcher/users/50692546 - The Witcher 3 Wolven Sword hiuuz
https://www.nexusmods.com/witcher/users/1166278, https://www.nexusmods.com/witcher/users/50692546 - Witcher 3 charaters