About the combat: well, one can always use the quick-combat option.
I've only played the Haven campaign so far, but I agree that it can get boring to fight 264 neutral stacks per minute...

Dorkus: Since I haven't yet played all the campaigns, I can't say whether the campaigns in homm5 are better or worse than in previous games. I can, however, tell you that I for one spent many many great hours playing the hundreds of community-created maps for both homm3 and homm4...

These are, after all, two of the biggest lacks this game has (imo): the lack of scenarios (I remember previous games had something close to a hundred scenarios, and each add-on brought more), and the lack of a map/scenario editor. Hopefully those will be released soon, and the community will get to work :)