Martial Power 2? Ugh.
I know they were going to do a new PH, MM, and DM Guide every year, but do they really have to do multiples of EVERY book now?
Do they have to? Eh, I kinda like the option, ya know?
Seriously, how many spells were there for 3.x? I'm not saying "wotc NEVAR gave any fighters/paladins/rangers/rogues ANYTHING before tome of battle", but with the exception of magic items, I feel that the martial classes were short changed a bit when it came to kewl stuff in 3.x. Now, we're getting multiple splat books seemingly for each power source.
I think this model works better; see, if they made "martial/arcane/divine power 2" in one book, it'd be bigger, more expensive, and some people would only use part of it. This way, people who want more "x power" get x, and just x.
To put it another way:
The 4E supplement model is more like a cafeteria ["I want the roast beef, two rolls, no veggies, and a chicken leg"].
The 3E supplement model is like a value meal ["I want the double meat burger, and i'm going to want a large soda, so make it a mega combo, even though I won't eat any of the fries, because it's cheaper if I just buy the combo; who wants my fries?"].
It seems like everybody gets more of what they want, and less of what they don't want this way, wouldn't you agree?