Much as I have a 'wishlist' as long as the drive into Corpo Plaza ( have commented on some of this in other threads) on features I would love to see, and agree with many of yours I firmly believe that most of them will be the province of the modding community just as it was in Skyrim, Fallout.
Being 'realistic' therefore on a DLC from CDPR, and given the scope of the tech problems and consumer disappointment in the feature removal content in the game to date, I would like them to focus on fundamentals to more create the world we expected from the hyped adverts.
Firstly, a FULL modding resource support kit, code release and whatever it takes to allow the modding community to fully improve the single player game as users wish
Fix the awful Police / crime system and replace it with something credible, realistic and sensible and allow variable setting levels, lets have car chases, robots, but not teleporting uber death squads.
Make the monorail/subway transport system workable with trains you can ride
Add 'flying cars', taxis, and air vehicles you can ride, purchase and / or rent
Dramatically increase engagement and interaction with NPCs, (not mission related) for example, allowing V to have interactive dialogue with far more characters, buy services and goods, have 'follower' assist in some cases, adult social interactions, variable random responses and NPC AI awareness of V that varies with situations. All we have at the moment are mindless zombies walking the streets.
Increase engagement with items and in-world articles. We can kick things, and collide in vehicles but we cannot pick things up, move them, stack them or move to create cover, or interact with things. We need a 'SIT' script on chairs, benches, seats, in bars, streets, clubs and on building surfaces or structures, with variable anims to allow us realistic immersion. When we eat/drink in bars and restaurants we need 3d workable animations just as NPCs have at present, but for V not the boring 'inventory' object as at present.
A more dynamic system of random events, robberies, accidents, crashes, fires, roadblocks, traffic jams, terrorist incidents, fights, disputes, parades, demonstrations, festivals and entertainment in streets and venues, and appropriate NPC responses in action and dialogue (not just the scared crouch)
Greatly improve the 'zombie-like' NPC system, improve the range of character types, clothing variations, walk patterns and spawn rates to create a true bustling world where it would be hard to see the repeat patterns
Reverse the decision on not having an official 3rd person view and produce the necessary avatar models, or offer support for the existing modding efforts in this direction.
Extend the process of avatar customisation, a much better initial creation process, and a full in-game 'bodyshop' approach for all aspects of appearance. Improve the entire body mesh structure to allow for much wider variations in physical form, 'cosmetic' enhancement, and 'visible' effects of cybernetic devices on the avatar appearance.
Vehicle upgrades, as well as air traffic, create boats for use on water, and dramatically extend the range of vehicles (including classic sports cars) and allow a full in game customisation system to produce player determined unique vehicle appearances, including decals, textures, colours, add-ons and in-game custom shops as part of the service industry.
Motorcycles in traffic ridden by NPCs... duh.. I mean why is this not there anyways.. similarly where are the police cars speeding to events with lights or sirens, tow trucks, fire trucks and air ambulances ( we see one only on that bathtub rescue mission)
Put back the 'adult' aspects of the cyberpunk vision, including avatar nudity where appropriate, a greatly expanded adult social interaction (joy toys /NPC etc) a red light district that is better than RL not a cardboard cut out, ok not a 'porn' game but at least a credible dystopian future adult culture as would befit a society obsessed with body augmentation and fashion.
Add in ability for V to buy increasingly affluent possessions, apartments, estates, and other status items with in-game status and wealth, including 'VIP' lifestyles and interactions
Fix the broken crafting system with the int_level0 bug and dramatically improve weapon and clothing customisation options
Overhaul the horrible V Fashion and get a designer who can show us some Jean Paul Gaultier/Blade Runner vision of future tech imbued fashions
Allow two handed combat, including dual blades, and shooting while driving etc
Missions, objectives, variety and thrills to support the real improved 'open world' that are NOT tied to the linear Johnny fixated dead-end storyline, something to DO in the game to keep it going for years, and we need to be able to continue ALL DLC with our original V character if we wish to
better stop here..... tip of the iceberg...