I know what you are saying Keith and understand fully, I think I'm in exactly the same boat right now.
What is wrong with my M8? = Nothing, absolutely nothing whatsoever as it stands as a digital camera. So what's the problem? I get far more joy in shooting my 50 year old M2 by a country mile than I do when using the M8, just the way it is pure & simple. 🙂 (For digital needs I have an Oly E-410 & Ricoh GX200 that really more than suit my digital requirements)
Trouble is, I just can't bear to part with said M8. If I sell it I really would like an MP but I could instead buy an M6 and a great Leitz lens instead of an MP which would frankly be a wiser choice if engaging the brain first, but that said a black paint MP does look rather tempting to say the least. 😀 {drool}