From my very limited experience with trolls (I just picked them up too

) I can tell you that the EBDT and the DTM are beastly in combat, especially if you can keep them next to an obstacle, as the EBDT gets a bonus to
def or arm and can grant that to someone else near him. Those two HURT being on the receiving end. pDoomie gives you some interesting choices as his feat is devastating, because it damages as long as focus or fury is spent or generated, he has a scroll that lets you choose the target of a frenzied beast, and can upkeep a single spell for free (fortune has been my go to spell for this).
But they're right, hes a might tricky to use. I would also also see about dropping the axer for the Impaler as hes no slouch in ranged or melee combat, but then you'd have a spare point to spend.