i wish. i think the i/o would be very hard to port well since half the fun of good 8 bit games lies in targeting the hardware and accepting the constraints like poetry.
but, anyway, i'd rather not use C because 6502 and Z80 are actually fairly incompatible targets for it from what i have read.
i wish for something more functional and fun. like PreScheme or Scheme48, where memory is manually managed. or some new form of concatenative stack language that doesn't suck.
(always daydreamed of using Haskell atom/tower types of projects, or esterel/synchrone family, to generate atari vcs racing the beam games more reliably / easily.)
But i'd also want things like static typing of my game code on the host PC that runs the IDE; and hot reloading w/ remote debugging on the target micro; etc.