One of my initial thoughts when making this post was that the sims 4 could never... 3+ worlds in one pack? No way. But I'm going to hope anyways. I believe both ts2 and ts3 had one vacation themed pack with 3 worlds so maybe it could happen for ts4... maybe competition will push them to greatness.
I wouldn't mind if each world were medium sized, similar in size to Selvadorada or Tartosa. I would be disappointed with a small 5 lot world.
I really like the idea of finding and building dinosaurs, that is something they haven't done before and I think it would add a new element of fun to the game.