The next guardians that will be added for DLC is Bilbo and Bert the Troll, although no date yet confirmed I believe.
Also try Ori, the Runekeeper, he was really fun! I bought Arathorn too, his playstyle seemed to be slow the hell outta the enemies and shoot em as they try to run, but imo wasn't as fun either, and Legolas I found was pretty disappointing too
PSN: Trannol, PSA:BR Main Gold Dragon Sir Daniel Fortesque. http://tinyurl.com/c7alxud
Legolas is garbage... I tried playing him in a bot match I pretty much geeked my self out at how horrible he seriously was even when I was the same level as everyone and whipping out all my skills did barely any damage... so much for a striker.
Sometimes you get the coal mine, and sometimes you get the shaft.
Agandaur is my go-to. You've got to be careful with Overcharge+Shockwave though, if you're paying a competent enemy with a silence, stun, knock up, etc, they can interrupt you, and since you've got zero defense, you die when they do.
If you are going to use him, investing in a good cool-down relic is a smart investment, as otherwise he's too slow.
I'm still a big fan of Gandalf. Dude annihilates soldiers for free, and not too easy to take down in 1-on-1 fights either unless he gets stunned/slowed/whatever else on top of it to really drag him down. Late-game that shield is an absolute monster of damage mitigation.