I'd probably want a bit more substance, what made it boring, to start with, but being boring, in and of itself is valid, if it's not helpful.
My point exactly. Obviously being bored by a game is valid. We all play games to have fun, so if the game is boring, then its not working as a game. But what I said was that "x game is just boring" is bad critique. For it to be good critique we would need to hear an analysis of, say, what specifically made it boring, how they could fix it, etc. To do that though a critic would have to try more than once on the game, because very often human beings find something boring that is actually really interesting, they were just bored by it due to their particular state of mind when they tried. If they came back to it with a new state of mind, they might find the very same thing interesting.
For example, sometimes I get bored by difficult challenges, because they're difficult, and when I am lazy I am bored by difficult things. Would it be good criticism for me to say "x game was so difficult it ends up being boring?" Obviously not, since overcoming difficult challenges is a staple of interesting game play.
