I hate to say it but anyone who thinks Naxx 10 is in an acceptable state needs their head examined. I can understand a 20% increase, I get maybe even 50%. But I go to the arachnid quarter and see Anub has nearly 400% more hp than retail 10 man naxx... 25 man has ~ 1 million hp more or less and you have 3x more DDers to kill it. If you think that is ok, like i said, you need your head examined. You are forced to do 25 mans or sit there and have a really unenjoyable raid you have to out gear to complete on 10 man NORMAL difficulty.. Yeah, call it "hardcore", and I'll call it what it is, moronic levels of tuning for the 1st tier of raiding in an expansion. Literally makes me want to quit.
EDIT : Straight from wowwikia.... Anub'Rekkan 10 man HP: 2,231,200 10 man(normal), 6,763,325(heroic) 25 man. Warmane has Anub at 7.8 million in 10 man.... in 10 man... in 10 man... Plain stupid if you ask me.