My guild doesn't raid Naxx yet, we are struggling in AQ40 atm. But I heard that some high end guilds don't even bring hunters to Naxx because their dps sucks compared to mages/rogues/dps warriors. Now as a hunter I outdamage everyone in my guild in BWL and AQ but they say that's due to mages can't dare to go full out but they can do it in Naxx. And they have so many more pots available compared to hunters to boost dps. Now is this true? If this is true, then I think blizzard messed it up because if no hunters are brought to Naxx because of this, it'll be harder for us to get our Tier3's.

P.S. My nuking dps in fights like Shazzrah is close to 500 (stable 500). If the boss has lots of armor though, it's down to 380.

You haven't got much to be worried about.

Hunters are still useful because not ALL fights are aggro independent. However, the rumors you are hearing are true to some extent because hunters top around 550 dps last time i heard. Mages/wars/rogues can exceed 550 without breaking a sweat. Aggro is a different ball game tho.

But people cannot forget the fact that hunters are pretty much the safest and most dependable dps as aggro is never an issue, mana conservation/regen is negligible due to FD => drink, and hunters are pretty heavily armored with a large pool of hp.

It's somewhat saddening that in my past guilds(Three different AQ40 guilds) hunters were the class who pulled aggro the most often.

Hunter DPS is fine. Look through the Sustained DPS thread and the various hunter mechanics threads here.