Sadly no situation will satisfy anyone. My two cents are : as long as you're nice and polite, asking people if they don't mind you gong nuts (a lot of times you'll get no answers but at least you did your part, you can go nuts and if they complain then what the hell are they on ?), don't go overboard and leave them at the entrance while you blast, and just respect other people (most of the time they won't mind a carry) there's no real issue to have.
I mean even during SL when we were much weaker (prolly 2-3 times less DPS on average I'd say), our damage was still noticeably higher than the average leveller cuz, well, that's what good gear for the level does. Back then I personnaly warned people because of a few experiences that turned out not to well as they kicked me simply for damage (and I was letting the boss pull, simply the damage beiing too high didn't suit them as the DPS felt useless and there was maybe a bit of ego in there idk).
My point being : there will be people getting angry at you, yes they are a minority but they are a loud one. Twinks already get a bad rep generally to a lot of folks even outside the loud minority so some people react negatively fairly quickly. Of of the few times I've met 11 twinks -that I remember at least- I've seen one 11 (or 10 idk) MW Monk that was super nice and asked us before going nuts, a fury warrior (met it on my Blood DK) that wanted to go too fast and got himself killed. Prolly not that well geared as my DK handled the mobs fairly easily. I've also met a fury warrior that absolutely melted stuff and we had a few runs, the first tank left as the warrior didn't answer him when he asked him to stop overpulling -which in a way is understandable- and I've prolly met a few others but if I have they surely weren't too great and I missed them.
There's a bit of everything, just keep in mind that there is other people playing, not just you. If they ask you to slow down or to let them fill their roles (tanks mostly) please be understandable. Maybe those folks are a bit stretched for time, they enjoy WoW and want some easy content to play their favourite class/spec and TW just fills the bill. Don't ruin the fun of other players, be considerate.
Now to be honest it's TW content. There were fellas optimizing this way before we lower levels got access to it. People will get used to it and to be fair, after running some -admitedly not that many, most likely around 10- TW dungeons in tha last 10 days, I haven't even met a single 11 despite changing groups everytime. The "11 pandemic" doesn't seem that bad from my point of view ^^
It's a funny fad though it does get a bit old when the forums get filled with threads all asking the same questions about the same subjects and those "junk volume" threads make the actually useful information harder to reach. The fact that most those folks won't even stay around makes it annoying.
Eh, it's not gonna last too long, at least not at the rate it does now.