I'm psyched about this park! Only a few problems. Please don't take this the wrong way, though. It's constructive critism, not hurtful.
1. Just one pathway going around the park? Try to split that pathway if you want.
2. Like you said, more theming. Try to have a theme for your park. ( Sceneric, Generic, Arabian, Pirates, etc.)
3. The Deja Vu type roller coaster, the corkscrews on the cobra roll look painful...
4. The pathway over the X-celerator looks a bit too big, try 2 or 3 tiles across!
Your park is going great and I would like to see more soon, hardtosay1227!