Crysis 2's story better be fucking fantastic.
Otherwise he will be the biggest laughing stock in gaming. Next to Ubisoft.
I'll reiterate what I said above. Why should his opinion be valid only if his own writing is good?
An interesting question. It's because of the subtext involved.
If it were me or you (assuming you aren't a game writer!) or Andy saying "these stories are for the suck!!1" it's an amateur's opinion. We don't have a true idea of what it means to write a great game, we can only subjectively say we don't like it. Valid opinions because everyone's opinion is valid, however un-/informed.
Because he's a professional in that field, we label him as informed and perhaps even expert, and assume he knows what he's doing. Taking that assumption further, if he knows what makes a good game, if he knows what he's doing, then he will natch deliver said good game. If he doesn't ... well, he looks kinda like an idiot because either: a) He doesn't actually know what he's talking about or b) He does, but chose not to do it. Either way, lulz.
At least that's my thought process. Thanks for making me go through the mental exercise of that.