Putting aside some of the ... development issues ... I think a pack like this would have, I do like it in concept.
Personally, I'd like the three worlds to be related some how. Not neccisarily geographically close, but maybe some sort of Lore Storyline that linked them... maybe with a "globe trotting" scavenger hunt type collection.
As for what worlds I'd want... I'm good with more or less anything that isn't US based, though things similar to existing worlds (not including Selvadorada, since we can't live there) would be lower priority than something based on somewhere new to the Sims 4.