Question: Is sent pvp viable before getting to 50 and unlocking all abilities/talents? I would be starting pvp from level 30 onwards probably.
Depends on your spec. Watchman is stronger while leveling, combat starts to shine after level 43 when you have the key talents. Before it is viable as well, but is even harder to play because you have to monitor all random aturu procs for bladestorm.
Sentinel/Marauders are definately good choices for alts, because they are so much fun to play.