I'm not 100% sure what the MA2s has, but some upgrades from the M2P to the M3P would be 60fps at 4K (the MA2s has it), Quad Bayer possibly, mechanical shutter would be nice, as would an optical zoom.
But I'm very happy now with my M2P. But we'll see next week when I get my hands on an MA2s. My M2P is 2 year old tech. If it weren't for the fixed aperture, I'd seriously consider the MA2s. Based on what I've heard.
The restrictions on exposure control in video is a deal breaker for me. If I want 1/60 or 1/30, I need to be able to change things more than 1 stop at a time. And I want to do that with aperture, not ISO.
But this is a personal preference.