Last night I ran into Dave at the Starbucks in Seomyeon. After he introduced me to his buddies and they peeked over my shoulder at my netbook and I explained what I was doing (working on Flying Swordsmen RPG actually), Dave and I started talking shop.
Mainly we were discussing the way that 3E to some extent, and 4E to a great extent, are written as if the DM is a moron. For example, the monster write-ups in 4E give tactics and advice for exactly how to use each monster. Modules include the rules again in them to remind you during play. Every mechanic, whenever possible, is boiled down to a 'universal mechanic' so you don't need to remember anything.
Maybe we were over-reacting, but it definitely is something that's there.
I don't think it's so much an Old School vs. New School thing, it's more of a marketing thing. Yesterday I was reading a thread on Dragonsfoot about how every Basic Set TSR put out was more dumbed down than the last. And can anyone seriously believe that a 500+ page RPG like Pathfinder is an easy read?
But there's an assumption in more modern RPGs that the DM can't, or at least won't, learn all the rules. Or be able to figure out how to use a monster.
We focus a lot on the challenge given to players in RPGs. It may also be time to think about the challenge to the GM.