On the one hand, I see your point. On the other hand, it's fairly common knowledge that a lot of time when GC's answering posts, he's at home. That he doesn't have an encyclopedic knowledge of every spell in the game really shouldn't be all that surprising. It's also not surprising that the top theorycrafters in a particular spec would know more off the top of their head than someone whose job it is to address the game as a whole.

Heck, there are tons of aspects of my job that I have to look up to get the details right. Why should it be so different for GC? So the next thing is to say "well, GC should only answer questions when he's at work and can look stuff up." I'd bet that if that were the case, we'd be getting a whole lot fewer blue posts.

Wow.
I'm work in support for a computer company as an expert on specific products, and I can say that if I spoke in an official capacity about product functionality that was outside my area and got it wrong, I'd be in a lot of hot water in a hurry. "Working from home" is no excuse, because spreading misinformation is a lot more damaging than keeping your mouth shut until you can be sure it's right.

I've played my SPriest for a few years now... and whenever I talk about spells and mechanics in a post I'm always sure to hit up mmo-champion.com and look at the spell list, or shadowpriest.com and/or wowwiki.com and eltistjerks.com to check mechanics and formulae... and I'm just some shlub shelling out my $N a month to Blizz. I would expect the Lead Systems Developer to be able to do at least the same, or at least email the text of his post to an intern to fact-check. The fact that the Lead Systems Developer can't take the time to post correct data/info makes me wonder what other decisions or statements he may be making off the cuff without full knowledge - and if this behavior has propagated to the other various devs.

I recognize the tenor of the post is meant to casually discuss things and not an 'official statement on the issues of X in class Y' ... but I would be no less worried if the President of the United States was chatting casually with someone over breakfast and made an error when quoting the Constitution. GC should know how these things operate if he is going to comment on them. I make sure I know before I comment, and I'm not paid to lead the development of WoW.