While most of their units are weaker than those of the other races, this is made up for in the sheer size of their force. Individual orc battalions are larger and orcs typically have a greater population count - not to mention that laborers and marauders train automatically for no resources. The ogre is the most powerful non-merc unit in the game and can wipe out entire battalions of men or elves. The berserker is another really powerful orc unit that, in large numbers, can devastate an army. Their ranged units aren't quite up to par, but they're meant to be a great offensive horde, not an organized defense.
Crappy castles... not true. Granted that some features such as additional counter-siege mechanisms and larger gatehouses haven't been implemented yet for the orcs and elves, the orcs still have strong walls with spiked gates that will kill anyone they fall on.
Economy... early game, it's great. They're nomads and hunters. And when they run out of wild deer, they can build a warg farm which will automatically train free wargs that the orcs can raise as livestock. They may pick up trading later in the game but overall, they have a pretty balanced economy.
I don't know how much I'll believe this game until I see it. It sounds ridiculously realistic and not vanilla...it's why I've been so excited for it for the past year but still can't believe it when I read things about the game from the developers.
Concerning the underpoweredness of Orcs...until you see something in action, you really have no idea. I mean, even after the game is played for a week or two, you still have little idea until strategies come out and you start to learn how to play a race to be most effective. And with all of these betas, wouldn't Orc players give feedback like, this doesn't seem to work or I have a bunch of units that can't do anything. I think we shouldn't be worried until the final copy has come out and we've played for awhile. Or get into a beta and play as orcs and give constructive feedback.