Honestly the thing I'm looking forward to the most is just playing it, which I get sounds a bit general but as I know my 9 year old laptop isn't running it then I don't know when I might get to actually play the game and so when that day comes it'll be huge for me.
I presume I've gotta mention something more specific though... and in that case it'll just be wandering around the world... CDPR make great worlds and having a completely fresh brand new one that I don't know any of the characters (aside from Keanu, ha) to meet and just marvel at the scenery will be a real joy, I'm sure they'll have made a game that it'll be super immersive...
I guess a bit off-topic but one thing I hope is that there'll be loads of ways to go about solving things (which I think I heard they'd do in one video), sorta like Dishonoured... maybe you can be well persuasive, or tech and hack stuff, or just go around kicking arse... and that'd lead to multiple playthrough feeling fresh... good mod support would be nice there too, but I've totally digressed.