Naxx stuff was completely killed when BC dropped and 20 minutes of effort got you a suite of things that outclassed it in every way.
The "Naxx-Level" items (if Naxx was still TEH TOP) are nowhere near as stupid hard to get now.
Well, except A'tiesh.
Lyrai; A very large portion of Nihilum was using tier 3 when they dropped Vashj. You are really, really underestimating the value of Naxxramas drops, particularly the set bonuses. IIRC, Warrior 5/8 basically completely elminated the need for hit in your gear set, and considering most of the early raid content is low damage, short enrage timer stuff, the extra threat more than makes up for the loss of EHP and avoidance.
Ironically, A'tiesh did not have incredible longevity when compared with the armor sets.
BTW, as for swapping weapons; Onyxia drops outclassed shit in outland until 64; Anything from late tier 2 or beyond could potentially last you until 70 if you weren't chainrunning instances for experience. Maybe if you'd done some raiding beyond the easiest shit to tackle in the entire game, you'd have some better opinions on how blizzard handled the item curving. Not that invalidating all the time we wasted on raiding wasn't a dick move, but honestly.
Most wings of Naxx trash were not that serious for a full guild ready to go in there. Certainly not along the lines of C'thun trash in AQ40. At least, full Spider wing, everything you need for the trash quest, and a good chunk of Death Knight wing.
I'd certainly rather do Naxx than Molten Core and its lava packs and excessive, excessive length of aughaiughagiuh. Or BWL and its lab packs. Fucking goblins.
For most classes, true Naxx-level items weren't outclassed until somewhere in the 66-68 range in BC for DPS classes. AQ40 items for other classes lasted pretty long also.
My guild went to MC back when we were learning Vashj ; A 20 person raid, all t5 equipped or better, and we still took something like 3 hours to clear the place. The trash is TERRIBLE. Not only does it take an eternity to kill, but it's completely bland and vanilla; nothing does anything actually interesting, with the possible exception of the core hounds, and any interest in the core hounds is quickly offset by the fact that you have to kill them over and over again until you kill the beast. And with the design of the place being so particular, and the HUGE gaps in ilvl from the front of the instance to the back, clearing it at the later levels of progression was... unreasonable. I'd love to know how guilds managed to clear that place in under 2 hours. Considering that 20 people at 70 is more or less the equivelant of 60-80 tier 2 geared people... I probably spent the better part of a month of playtime in that place, and we still never cleared it in under 5 hours at 60.
t paco; I would love to play FFXI again one of these days. I honestly found my experience there to be overwhelmingly pleasant - when I was actually fucking playing the game. My only complaint with FFXI was time spent LFG. It's good to hear an educated opinion, rather than one generated entirely from watching videos of the shit that S-E threw out for the insane/fanatical japanese who were complaining about there not being enough hardcore/unkillable shit in the game.