My dream for this would be "Sims 4: On Tour" either gamepack or Expansion pack, with bands and cars, and the world maybe being not so much one large world, but three smaller ones, one with a bar (with stage) one with a variant on the Nightclub lot type, and one with an "arena" lot type, so you can play progressively larger venues.
Obviously, if it's a game pack, it wouldn't come with three neighborhood sized worlds, just one neighborhood type world that was some sort of stopover town (Think Strangerville, but without the strange - and maybe not American Southwest in feel)
(Okay, what I'd really like is a selection of single lots you progress through like Rock Band's World Tour mode, but I think I can safely say I'm alone on wanting a world like that.)