The current six speed is a really great tranny, especially when you put an aftermarket shifter on it. Doesn't break, and that overdrive lets you almost idle at 70-80mph.
Really what they should focus on the next Vette isn't more power, as honestly the current cars are already some of the bar none, fastest production cars you can buy. I'd like to see less weight, less length, less width, make it feel not so clumsy and more nimble like a Miata. And please get a decent interior in there with those Recaro CTS-V seats in it.