4. Further Variety
It seems to me, as a relatively loyal AC fan, that each new full title in the series has offered a little more depth and variety than the last. And AC III most certainly continues with that trend. If you're not in one of the two cities, you're in a vast forested wilderness; if you're not there you're at your homestead, a village that you basically get to establish and populate yourself; not there, then you're out at sea, fighting the good fight come rain or high water. I'm not going to list every gameplay feature that's on offer - that'd take far too long - but suffice it to say, there's a lot; much more than there ever has been before, I'd say. And if greater gameplay variety doesn't make for a better overall game than I honestly don't know what does.