Interesting build Malim!
It's probably not relevant, but I tried to make a melee Mentalist in RMU as well, and it turned out surprisingly good. It is expensive, but you can buy two ranks in weapon per level in RMU, which makes the build a bit better offensively. I gave him a Polearm, but you could go sword and shield too for the extra DB. Then he has spells for ranged combat. For armor he was in leather, moving towards the heavier leathers, by level 5. It worked out surprisingly well.
In RM2, though, I agree that going with Adrenal Defense is probably the better way to go. The cost of maneuver in armor is rather high, and soft leather really isn't worth it. You need to either go rigid leather or chain, and those cost a lot.