Cenccu: Why Might and Magic: Heroes? Why not Heroes of Might and Magic?!? This is outrageous! This is disgusting! Are they making so crappy game that they dont dare to call it Heroes of Might and Magic?
http://might-and-magic.ubi.com/heroes-6/en-GB/home/
Have you taken a look at it? It's actually pretty heavily drawn from HoMM5. There are some significant changes in the way heroes are built, and there's a system to allow your "alignment" to factor into the characters you make, but unless you're doing the always-hard-to-catch internet sarcasm thing, it's kind of premature to be hating on the game.
As far as the name change, it may have something to do with licensing as suggested, but I doubt it since Ubisoft did the last Heroes game, too. They've mentioned a few changes in the system, a streamlining of the RPG mechanics and a broader differentiation of races. Not surprising since it's made by a team best known for RTS. It would also better link the franchise if Ubi is planning to come out with another MaM title in addition to the HoMM (MaM:H6) title.
I think cautious optimism might be the way to go here, unless you really hated HoMM5 and the recent King's Bounty games. In which case, go right ahead and hate away. You won't miss out on a good game if you manage to convince yourself it sucks sufficiently ahead of time. =)
edit: typos.