What I really want: a reinvention à la Metroid Prime (or that Maverick Hunter FPS prototype). Not necessarily in first person, but still 3D. Same classic concept, same characters, same charm, fresh gameplay. They could take their sweet time making this because I don't want another X7. Dream developer for this: Platinum Games (Kamiya as director)
What I'm cool with: something like MM9 and 10. I don't mean 8-bit, just that level of care and creativity. 12-16 stages with interesting platforming, a solid arsenal and maybe a new power-up or two. I don't need a Mega Man Metroidvania, a sandbox or anything too complex.
What I would desperately accept right now: something like MMX6. A mess of a game that somehow works. Weird, challenging and open, using an engine that I'm familiar with. The only reason I even bring this up is because we all know Capcom.
What I do NOT want: MM6 slide physics, MM7 huge sprites, MM8 slow pacing, X5 text skipping.