I'm asking because I have no idea if this would be genuinely useful as opposed to 'Oooooooooh pretty'. The latter is nice but serves no purpose.
As more themes come along and people ask instead of just clicking and seeing, but also to maybe identify what might be nice given current choices, how about a theme matrix?
A side-by-side feature comparison of every theme.
If it really would be something useful, I'll put one together. I can't decide if it would or not.......