Here's a weapon/power-up I have always wanted to see in a Wipeout game:

Teleport

You could have it fire out in front of you, much like the force wall did in WO3 and it opens up an Einstein-Rosen bridge. You fly into the portal and you arrive instantly a couple of hundred meters down the track. You would have to be careful though as it is only stable enough to allow one ship through, so you would have to use when no opponents are immediately in front of you, else they might fly through the portal ahead of you and steal your advantage.