I think Sony would be ready to pounce on Firesprite if they made a game too similar to Wipeout and called it something else.

If they do make a futuristic racer, it could be so vastly different that maybe Wipeout fans wouldn't be interested in it.
Fatal Inertia is a classic example of this.

The genre of futuristic racing has always been hampered by each gaming system having it's own take on it.
Playstation with Wipeout, Nintendo with F-Zero, Xbox with Quantum Redshift.
Wipeout has been doubly hampered by having it's last two new games only released on PSP.

What's needed to get the whole category back in the public's attention is a killer racer that is released on all consoles.
When you pared it right down, it only really needs 3 basic things.
Great tracks, great craft physics/handling, and a online leader board to update your recorded times for each track/speed class, the rest is dressing.