Sounds interesting. Has potential. But I'd prefer it if it were just PS5 and came about a bit later next year.
It's totally possible that I'm full of it, as I gave up PC gaming a long time ago, and maybe things are way better now.
I'm a big PC critic who left PC gaming for about 12 years, but came back last August. Things are definitely better now, but only really if you buy a pre-built PC. Building your own makes it ten times the work and stress (though of course far cheaper).
In the state of PC gaming today, is it pretty well guaranteed that I'd be able to park my ass on the couch and use a DS4 controller?
Every game that releases today: yes. I do every day. Played all of SOMA, Assassin's Creed Syndicate and Mad Max like that. Was great.
Most games from the last 10-15 years: yes, with a little bit of work (download/install a program to make it think the DS4 is an X360 controller, then play with almost no issues.)
Games from before 1996/1997: Nyehhhh. Yes, but lots of work.
Another big problem is my preference for relaxing with a controller, as I like online MP games and playing against keyboard+mouse players would really suck.
I've played the Division and Rainbow Six Siege on PC with a controller a lot and not noticed too much. IMO a controller is 85% as good as KBM and strategy/clever play wins out the majority of the time.
How much time do people spend these days fiddling with drivers and so on?
Very little. I only update once every couple of months, and when I do I just click on the 'GeForce Experience', click 'Upgrade driver', click on 'Express install', then it's done in about a minute.