ARC has two main problems right now, and addressing them would fix the balance issue:

#1 They're lacking a 3000TP WS, which is where everyone else is getting their damage.
#2 They're the only damage class that's subject to animation lock to perform regular attacks (Light Shot).

It's silly, though, to argue that you deserve to be the top DPS just because you need arrows. Arrows should just buy you range, not DPS.