I like DW, although I feel some of the changes away from the base AW aren't necessarily for the best. That said, I don't think it does really handle power tiers all that well, and I think that's kind of intentional. It's a game where a Dragon is potentially just as valid an encounter for a starting group as it is for a level 6+ group.
You gain moves and some stat bonuses with levels, but you don't drastically change in power level, and 'tough' monsters don't generally have massively more hit points than middling ones, just scarier moves. I think it works better for the average D&D game, but not as well for an Exalted in which you want to play up the Celestial types (Exalted and Divine) towering over the inhabitants, which is what I want for Myth World.
I'm not going for full-on gonzo straight off, but I'm more interested in including the high end than in supporting low-level activity. Games like AW and even DW are good for that, I want to explore something a bit higher tier.