Rush killed the cat!

[Snowaeth]

It seems you didn't get an archer/brd claiming everything before you're in range to even use provoke (more range than shield lob/tomahawk) xD

Even if is not the case, as a marauder 27, if dps were lvl 50, they can do more damage than enmity generated by the tank. Yes, there is leve-sync, BUT a level-synced lvl 50 characters who knows his skills can steal agro from tank if he goes ape-sh*t. When i did low-leves for Atma Books with my monk i joined parties with some good tanks (not 50) and sometimes i had to stop my dps to not steal the mobs (and yes, i was waiting for the tank to claim/get hate and attacking the mobs marked by him)

If you know which skill does what and how to use them, no matter which dungeon Tank aggro > dps aggro.
(Back in 2.0 gear mattered quite a bit in here too, but since 2.1 getting threat on tank is trivial even when you'r way under-geared compared to the dps)
I do understand that a learning tank still wouldn't know how to pull this off properly, but for low lvls, when in doubt spam flash/overpower = gg.

Dps have no increased aoe emity skills at any lvl, tanks do. At best with burning all of his cooldowns the dps could get heavy threat on 1 mob which could be reclaimed with proper provoke timing or comboing if you don't have provoke yet (easy way to stop dps from taking dmg for a while during the reclaim period is to stun the mob).
There's nothing wrong with using flash/overpower more than once. And properly spreading the aggro combo between mobs will make the dps never able to keep up threat.

Also positioning makes things easy.
If the archer is aggroing the mobs there's only 2 ways the mobs will go, either to him or to the healer that will heal him. Guess where you have to be to get aggro back?