Okay, so I came up with a few ideas that might be fun...
First, have an access to Sunset valley stadium (or arena)!! I mean its very big, and there could be a couple of superjumps off the grandstands and other sweet sweet stunts (like airfield )
Then, a new car collection to burnout store, Crazy car pack! Yeah it souds very silly, but imagine a go-cart, a TANK or monster truck or scooter driving around the paradise city! Think about it...
And last, more, different traffic cars. I am bored to see all the regular cars. A van, bus, basic car, limo and so on.
These were my ideas, post replies to comment and/or suggest more stuff that paradise needs!