Neonchameleon
Legend
The striker in question is a hybrid PHB 1 warlock and PHB 1 rogue. I don't know if I'm exactly right on this, but he seems to reliably deal 7 points of damage when he hits. (Other strikers seem to be able to deal much more damage a round.)
7 damage is sub-baseline. For the record, a halfling bard with a shortsword and charisma 16 - and no supporting feats (which is almost as far from a striker as you can get) should be doing 6.5 damage per hit.
7 damage to me sounds like a rogue who is not getting combat advantage - with combat advantage a rogue does 2d6 extra damage with a dagger. Or a warlock who isn't cursing (for d6 extra damage).
My belief is that your Warlock|Rogue would be better in just about every possible way (including at thievery) as a Warlock (or Feypact hexblade for preference) with the Rogue Multiclass feats. And that Hybrids are one of the very few things in 4e I ban (actually, I find it easiest to simply ban every class in the PHB3 except the Monk and this makes up my entire ban list).
As for your battlemind, urgh. Walk him through the minor/move/standard. Or ask him to describe his character and whether you can rebuild based on that. I'm thinking Knight or Beserker.