I know this is a bit late, but I feel like it's still topic-worthy.
I'm actually kind of glad that terrain is being taken out. It will force people to create bigger and better builds. We won't have "Slope TDM's" with a box on either side of the mountain range and have that pass for a server. People can strategically build the terrain to suit the needs of the server exactly. imo, it will make for a much better server experience.
Now onto vehicles. We all know that currently the vehicles are pretty bad when it comes to driving on nonflat bricks. When a hill is built, most people tend to use either bricks or plates. Now, asking for vehicles to drive smoothly over bricks is just plain stupid, but I think that we really do need the vehicles to drive well over a slope made of plates. Vehicles will have to be updated in V22.
Anyway, that's my rant. Opinions? Anything to add?