Well, this does kinda scream, "Not as good as Xbox 360 and PS3!" The only fathomable reason to hide the specs if Rev is equal to or greater than the competition is because Nintendo wants people to judge the system on it's other merits. The problem with that is, the hardcore crowd will judge it on technical merits anyway, and as some have said here, hiding them leads everyone to the assumption that it's the weakest...
Umm...back to the point, as usual, it sounds like Revolution will be the weakest. Which doesn't matter to me that much, but what is driving me up the walls is that I want to know what the games will look like; having specs or a rough power comparison to the other consoles would be the give me an idea, but Nintendo doesn't want me to know how it compares to the others so I sit here aching to see some screenshots.
How will this affect Nintendo's sales? I don't think it hurts any more than having specs that prove Nintendo is the weakest. Nintendo plans to sell the system on the merits of the new controls, so as long as the graphics are better than the Xbox, I don't think matters. Of course, maybe Revolution isn't the weakest of the three. In that case I think it would probably be better for Nintendo to reveal some specs, although it could still be excluding itself from a big chunk of gamers if the system is better than Xbox 360, but worse than PS3 (assuming PS3 is actually the most powerful).