I like the idea of using weapon pick-ups as boost energy. How about have a boost bar, and every time you drop a weapon it gets stored as boost energy?
The only thing I would like to see is the game to look a bit more gritty, like the original wipeout and 2097. Everything, from the environment to the sound fx should be harsh and a bit dirty. I want the game to sound like I'm at an arcade in the 90s.
If you have billboards placed above the race track, maybe make them holographic. I always hit billboards in some of the later wipeouts because they placed them right after a jump or bumpy area. In the psone wipeouts the billboards weren't solid and you could just fly through them.