Q u o t e: i don't think that can work with only 7-10 levels for a whole difficulty level.
Your math has failed you. it would be about 20 levels per difficulty. probably more for normal, and a lil less as you advance in the game.
Level caps are generally irrelevant to the game. If they scale the game to a level 10 hero, 10 levels is all you need. Heres the only real concern i see there could be with a low level cap. A low cap = slower leveling, where as, if the game had 700 levels, youd get them constantly. This means that as you level slower, there will be less of a difference in the monsters strenght between areas, and eventually a character should be able to survive a zone that is too high for it.
- does that make any sense? - i can try and explain it further. i get the feeling i got too messy in my explanation.
Anyway. Technically they could make it easy to get to level 40, and then make it take years to get a single level from there. My point remains. It really doesnt matter. youll have the skills blizzard wants you to have in the end. Less levels just means skills wont require 25 points to be useful, but way less.