Here is what I want on the tech side:

-One huge game world rather than 4 separete pieces like in The Witcher 3

-Reduced loading screens

-More stable frame rate

-bigger game world (at least 10% bigger)

Gameplay:

-A good protagnist

-More items and crafting items

-Ability to buy property and earn coin

-fishing

-one more addition to the complexity of combat

-own property and decorate and have your stash of items

Other:

-Continue the great music and awesome dialog

-Expand upon the witcher 3 and make it twice as good!

-More variety in question marks on map

-A level up system that goes to 100

Multiplayer:

-Maybe split screen/ online co-op? Or maybe something like GTA5 online?

Better performance overall, improvement over the systems in general, and same setting, but totally new story(nods here and there to the older games, but completely new charachters and such).Having that done, I hope that they also have surprises, new things that i wouldnt expect.As long as they are good of course.Oh and the magic system.Needs to be more diverse and more useful.

more Cyberpunk 2077

Hmmm. More of the same for the most part. Give a lot more money when you sell things. More variety in attacks with the swords.

Nioh combat
Or no combat at all

I thought I heard The Witcher series was over with 3? Unless I heard wrong. If I'm incorrect could someone let me know?

More nudity. Maybe throw some naked man penis in there too to add some variety.

More Sex on Magical Creatures! On a dragon perhaps

I actually don't want Witcher 4...I find Witcher 2 to be much better format for telling Geralt's story, open RPGs generally work better with "nameless hero"...so that is what I actually would like to see them make, more of a classic Sword & Sorcery open-world RPG.

But if they chose to make another Witcher, I hope they take even more cues than they already did from Gothic in TW3, specially when it comes to some of gameplay mechanisms.

Oh, and this one is actually most important for me - no more flat Velen alike landscape design that relies heavily on map markers.

Witcher 4 is not happening, at least not for another 4-5 years. CDPR is currently working on Cyberpunk 2077 and thats like 2 years from now.