IF dancer was confirmed, and IF they'd ever have a job that branches off something else again, I'm quite certain it would be arc/brd.

I can't get myself to believe a dancer to be some kind of pure DPS thing. To me, it got way more of a supporting role. Buffing people, reducing their CDs, refreshing MP/TP...
Hell, I can even imagine it better as a healer than as a pure DPS.