You don't need to farm. Get on teams doing level 50 +4 missions and have 2x XP on. That's how I got my two level 50s in their final stretch so far. I also found focusing on a melee, DPS, and support build and getting them to 50 helped curbed altism a bit. This way there is a bit of rotation and change in playstyles. Once that group gets to 50, grab another. It also helps to figure out which builds once they hit 50 are still going to get played and invested in and focus on those. I had a list of like 16 guys. I'm down to 9-10 I care about to get to 50. I can see 5 being played post level 50 and one is a farmer so that's a default. I accept the fact I'm not going to pimp out all 10 characters, so I focus on the ones I want to. I play the others as a way to take break as needed.