There's also 2 things to consider if you wanna see your dmg vs other players.

1. Some DDs sux ^^ (I know some who can fail their combo even in arc.. :/)
2. Some DD control their hate. They slow down DPS so they don't get 5 mobs flashing red on them.

So if your pt got DD style #2 and if your are really agressive and you don't control your dmgs, yeah you can be top DPS. But i'm sure if you put a naked ARC vs a double-melded ARC in the same conditions and with the same agressivity, the DD with good gears will do muuuch more than +1k dmg on a 20 min fight.