3). All the healers and all the tanks are viable for ranked play, juggernauts and power techs over assassins and mercs and Ops over sorcs, but all are viable and it all comes down to personal preference and group make up.
Some Sage Healer players would doubt that. Especioally when it comes down to an Arena.
I admnit, though, that more hardoce PvP players do not believe Gunslingers to be viable for Ranked PvP, either (my main char is an Gunslinger, and I have read enough times that they do not want the Gunslinger class in Ranked Arena).