There will still be lots you can do and see, even if you don't fit on everything. Any iffy rides have a test seat outside.
If you are a Harry Potter fan, Hogsmeade is really incredible and interesting, even if you can't ride HP and the Forbidden Journey. You can walk the full queue with your party, and it is worth seeing. There is also a "castle tour" line that lets you experience the inside parts of the queue (you miss the greenhouse) at your own pace. I enjoyed taking the "tour" to get pictures and watch all of the character interaction scenes in the queue.