Oh I'm not saying it wouldn't be fun, just that neither of those games are procedurally generated with "endless" content attached. The South Park game was effectively like an 8 hour hilarious south park episode, so it was great. But it has some pretty limited replay value. Dota 2's announcer pack is like an hour? Or something similar of unique statements about what people are doing. Far cry from limitless content. Since the vast majority of the humor comes from the unique interactions between the characters and "scripted" events (Yeah, I know that a lot of Roiland's stuff is him just being drunk and recording audio and saying hilarious shit) but it would be totally different for them to have that type of unique sort of humor on -every- dimension/planet/whatever. Not saying that it couldn't be done, but just saying that for simplicity's sake they'd have to make many of the statements super generic, which would take away from the humor.
Granted, I could be wrong. I'd play it regardless, but I would be surprised if the level of quality was maintained after multiple dimensions/worlds/whatever have been visited, and that material wasn't being reused fairly often. "Endless" content has a bad habit of being bland content, hah.