So I had my first raid night last night. Only one kill, and it certainly wasn't Wrath-easy. Where the much less-skilled guild (rank 5000-ish) I was in this time last year was able to kill three bosses on the first night of Icecrown Citadel, my current world top 200 guild took an hour and a half to snag our first kill. We also wiped for another hour and a half on the second boss. To be fair, some of the difficulty is not having timers and no released, solid strategies yet, as well as some undergeared healers, but so far the fights are way more fun than they've been since Ulduar. Love it.
I can't speak for your raid, but the biggest obstacle I'm seeing, in general, is DPS mindset of, "lol i'm standing in fire. it's okay to stand here for a few seconds though because healers will heal me." With mana gen regen the way it is now, this thinking is toxic and will undoubtedly lead to oom healers (again, just sayin' in general since I'm nearly 85). Instances themselves almost require a guild run because of DPS still standing in fire/not avoiding cleaves and tanks' old mindset of "healer has 50% mana, i'm pulling nao".
I'm betting that heroics are going to be a total pain in the ass if you pug it.
As a tank, I'm not pugging at all. I don't trust pug healers, I don't expect pug DPS to be capable of proper CC and kill order, and its generally not worth the hassle when a guild group now one-shots everything in heroics with little difficulty (providing they're awake). As for raids, mechanics so far are a little more interesting. The first boss we engaged (not counting the Brutallus-esque VoA flavour boss) was a typical council boss, with a bit of a twist. Only two were active at a time, and the dangerous part of the fight was the synergy of their abilities: one would chain lighting while the other dropped a buff for the raid to stack in, for example. If people weren't on their game and paying attention, a wipe was assured.
The second fight was pretty standard AoE-damage and adds, but again with a twist. Anyone hit by adds was infected, and the add disappeared. Ten seconds later, a full health add spawned where ever the raid member had moved to. Meanwhile the boss did heavy AoE damage, stressing our healers mana and putting the responsibility on the DPS (especially the melee, who weren't killing adds) to get the boss into phase two for a short mana break before phase one repeated. With the dearth of raid boss guides (Tankspot has since put out a guide for this boss, ironically enough from the other top guild on my server), trying to find a strategy to deal with everything was taxing--all we really found out is that tanking them may not be the best plan.