I managed to rush myself to level 80 just in time to join some folks in my guild and other friends for a 25 man run in Naxxramas. We cleared out the Arachnid Quarter and the Plague Quarter, six bosses, and took a couple of shots at Patchwerk. It was fun to get back in a big raid, but boy is it different from before.
Trash clearing was fast and sloppy, all AoE tanking and AoE damage. Honestly it felt a lot more like post-3.0 nerf raiding than the old careful precise pulls of before. The spider quarter was nothing, really too easy. Plague quarter was a bit trickier, we may have even wiped on trash once or twice, but still no great challenge. Bosses weren't much harder trash. One-shotted most of them, only wiped on a couple when we had the wrong strategy. (Note: Grand Widow Faerlina is quite different in 25 man.) We wiped twice on Patchwerk before calling it for time.
All in all I was a bit disappointed. We have strong players, and some folks have already accumulated significant gear at level 80. But I was hoping for more of the intricate, complex stuff of earlier raiding. Like managing Moroes and his adds, or dealing with the ogre trash in Gruul's Lair, or cube clicking in Magtheridon. We mostly outmuscled the first two parts of Naxx, Heigan was the only really complex fight. Then again this is all entry level raiding now, I'm sure it will get more interesting as we move deeper.
I had a great time, and there's a lot to learn about being a level 80 feral. I hate the AoE tanking, but if we're going to do a lot of it then it's clear the Feral Instinct talent will be essential. My cat DPS was crappy too: 1800 on Anub'Rekhan vs. 2600 for our best (a hunter), 2660 on Noth vs. 4000 for our best guys). There's so much to manage with cat DPS now, I feel like a DoTlock. I'm confident I need a custom addon to help manage the rotation.