The ARC can physically dodge (re arc dodge) the Defender's hits
The only pure combat ARCs are Thane (far cheaper than a defender; shouldn't put up the same fight) and Norra, who can either tank for days or dance with bb8
Norra with a tail gunner won't have much issue with defender agility; with bb8 she'll have little issue arc dodging the obvious Ks while applying her rear arc
The fact that defenders are far more effective at high speeds while the ARC is more effective at low gives both ships vastly different areas of strength, which will make it a manuever war more often than not. If you can stick near a defender with bb8 rolls,you won't have much to worry about
Bray and Shara aren't really combat craft (they're a stress hog and jank support respectively)
Edited by ficklegreendice