That saber makes absolutely no sense. Unless he is a TRULY amazing swordsman and won't cut his fingers off when twirling it about, I foresee damage. I mean, double bladed, that was fine and believable. But the two small beams...that's just pointless and dangerous.
And I believe it will be a main character, he's not an actual Storm Trooper. Because they STILL used the clones. I may be wrong, but I do not recall seeing them say they stopped using the clones during that era. The only time they were seen without helmets on was in the prequels, in which we saw they were clones. (Jango Fett) In the cloning facility that Obi Wan visited, during the battle with General Grievous, etc. One was never seen without a helmet/suit on during episodes 4,5, and 6. Regardless, I hope J J Abrams didn't screw this up too badly. I LOVE this universe and would hate to see it destroyed.