If you lean towards a 28mm then an M2 isn't going to be much good unless you use an accessory viewfinder. That isn't itself a totally bad idea as you get a big fat 28mm window on the world, but it does slow things down when focusing in one window and composing in another. The M2 does however offer a very clear 35mm viewfinder frame.
Personally, and as a glasses wearer, I'd suggest an M4-P. It often isn't possible for a glasses wearer to see the whole frame in one go, but most soon learn to quickly and unconsciously scan the edges of the frame to see where things are. Glasses that can be pushed against your face with flexible frames are also a help.