For a fresh 90 with iLevel 440 who just started with Heroics?
I think 25-30 is a much more realistic outcome. Yes, 480+ iLevel tanks will outperform them, but who cares, honestly? Heroics are piss-easy as it is.
Bad enough that my Warlock (Affliction) alt got kicked from two heroics today, because I did 18k DPS on trash when everything died in about 5-6 seconds. You don't really expect me to reforge/enchant my 437 items or put a belt buckle in my 429 waist, do you?
This. You'll also get people like me on my Balance/resto druid - I usually heal but sometimes queue with a guildie who really wants to heal so you're getting someone in caster leather that's reforged for healing doing a DPS role. Single target my dps is about 25k... aoe in larger packs is better of course. But the fact of it is that the single target boss fights last, maybe, 15 or 30 seconds longer than they would otherwise. Sorry but that's just not material in anyone's life.
Now, if I could reforge in a click back and forth between dps and heals I would but I'm not going to manually reforge back and forth for a heroic or two. a raid? Yeah, I'd spend a few minutes reforging correctly... but for a random 5 man? Please...
Hmm i haven't noticed this, i'm at the same level (88) and as a frost mage i'm usually doing the lowest damage done at about 25k dps. Then again i tend to move around a lot to practice avoiding damage so my activity is also usually the lowest. I usually see people reaching ~35k dps in the dungeons i've been doing, the top offenders being enhance and ferals. Hopefully once i get my lvl 90 talent (all which sound horrible to use) i'll leave these guys in the dust, but whatever, i pvp 80% of the time.
Also keep in mind that there is an absolutely huge gear gap at level 88. There are people with 372 weapons going up against people with 450 weapons, on a caster weapon that's about 2k difference in spell power.
Then there is the fact that you don't need to be pulling high level dps in dungeons, or do anything. Compare this to BC where even the highest dpsers in your party could get kicked for failing at combat mechanics and CC, now it's just like meh whatever, even if someone is doing less dps than the healer people don't care. This mentality is only really hurting the quality of players that are coming through to lvl 90.
In the cases of newer players they've gone through 'vanilla' dungeons where the tank has been doing 80% of the damage done and the dungeon is finished in ~10 mins. You can't really expect them to somehow learn late game concepts from this model. Half of them probably wouldn't even know how to maximise their dps as the tank has been 2 shotting mobs before they can get a 2 second cast off, thus you see a lot of people resorting to instant casts, mages continuously spamming icelance etc.