However, all the new buffs and debuffs can make a raid leader's head spin, in case they do decide they want to organize a raid so as to optimize buff coverage (and surely some raid leaders will want to do that). Fortunately, MMO-Champion has made an outstanding web tool to help you figure out your raid composition. Just drag-and-drop specs into the raid groups, and check the right-hand column to see what buffs and debuffs you'll get.
It will also tell you whether you have the best buff in a given category; in my sample raid comp (my last Karazhan run), for instance, we only have Battle Shout, which is not as good of an AP buff as Blessing of Might. If you're missing a buff and want to see how you could get it, just mouse-over the buff, and it'll tell you what classes bring it. The one thing I really wish this tool had that it doesn't is a corresponding ability for specs: mouse over the spec and it'll tell you what buffs they bring. Overall though, this is really useful; I'm not a min-maxing raid leader (or a raid leader at all, actually), but I'm probably going to make use of it just to check what my raids and groups be getting. And because it's really cool.