I've spent a lot of time on this game already upon release however there have been some pet peves for me.
I'm going to suggest some mods that might be doable but not super unrealistic ones.
Firstly, one of the first things I noticed in this game was the first person camera height. If there was a way for someone to create a mod that adjusts this height I will be forever in your debt.
Secondly, in one mission you can race against other opponents. During this you get a shard that puts a driving line on your HUD. This HUD includes a driving line, seen before in games like Forza. This is the biggest stretch on this list but maybe there is a way to implement that driving line into the waypoint system to make the game more immersive and decreasing the amount of time you look at the minimap.
Next, the minimap zoom is far too zoomed in. I was privilaged enough to play the game prior to release and the minimap was more zoomed out. This brings me to believe there might be somewhere in the files that can change the position or zoom of the minimap.
Also this game is very grindy in the aspect of the damage you do to some enemies is essentially the same as getting water in a sponge. Maybe there is a way to greatly increase headshot damage with some/all weapons if even possible.
The other mods I would request would require some sort of genuine mod support from CDPR. I hope they include something like this in the future as, like other games like: Skyrim, the game can be generally fixed with hard working modders from their respected community.
Side note: This is a list I came up with from looking at this forum, other forums and game experiences to suggest (maybe) achievable mods. I hope this post can help summarise the easy-ish problems that could be fixed within this amazing game.