2 classes of award? There are like 20 iterations of miles between 6,000-50,000 on just the one example I gave. It makes no difference if some are called web specials and some are called MileSaver and some are called aanytime (which, aren't even the max redemptions AA asks for because, as AA says, "there are select dates that require a higher number of miles"

If we are talking about two options:
A. 1 cent per mile on whatever flight and cabin I want to take
B. 0.5 cents per mile on the flights I would want, 0.8 cents per mile on the flights I would accept, but heck, up to 5 cents per mile if I agree to massive inconveniences and spend hours searching on AA.com over months seeking out the right combination of miles, destination, flights that aren't torture. (and shoot, 5 cents per mile is generous. The last few web specials I scored still only ended up being worth about 2 cents per mile because the cash price was low anyways)

I find more value in option A, even if that might "cost more" than certain scenarios in option B. Time and flexibility matter.