The idea of the "flatter" blade is not entirely true. If you look at, say, a Gold Seal, which is definitely an "advanced" competition profile - the blade has an extremely aggressive rocker. The coro Ace has a different rocker than a Coro Comet (which is quite flat) - yet, they are both intermediate blades.
The Legacy is closest to an Ace, which is not a flat blade; it's got a decent rocker. I know of many skaters who are very happy in them.
This "advanced" vs. Intermediate seems to be a Jackson thing; if you look at the Wilson blades that they are comparable with, they make reference to things like the toepicks (bigger as you move up in level); strength, etc. Jackson "splits" the blades up into these levels, and they assign what we would usually consider as mid-range as Intermediate (Wilson CoroAce, CoroComet level); and everything above as "advanced" - (the Pattern 99, Gold Seal, Gold Star level.)