It's also important to note that without M&M there would BE no Diablo and it's clones...But M&M STILL kicks the livin shit out of ANY Diablo clone!
Um... Couple of things.
- Diablo was a real-time roguelike planted pretty firmly in more combat-heavy Moria/Angband style. M&M cannot really be considered as a predecessor in anything more than a really minor, by-proxy way.
- The Bard's Tale, Wizardry, and Ultima all actually predate M&M as a series. Wizardry and Ultima both by about five years, at that. All of these had a pretty big effect on how RPGs stared shaping up down the line. You can't really single Might and Magic out here. See point above.
- Diablo also came out two years before M&M6, so you DEFINITELY can't say that 6 had any influence on Diablo.
- The phrase 'Diablo-clone' is sort of meaningless because Diablo did not invent that style of gameplay. Rogue did, in 1983.