Arch/Mental or TA/Psi?
Just gonna throw this out there that Arch/Mental has been mowing down mobs for a while now. I've never actually considered TA to go with anything other than Arch. It would be an interesting combo, but hey, it's your character. Just know that the Blaster will do a lot more damage than the defender will, and who knows. Maybe you'll find the next farmer. Heh heh heh.
RAWR.
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Archery/mental is what I would reccomend, simply because it would be the most different from what you've already seen. You've seen the psi side do damage as your dom, now see how the archery handles as a blaster.
The blaster leans more toward AoE damage, the defender leans more toward AoE debuff and denial. With some overlap, of course. Try to get a temp/dayjob power with fire or energy damage if you go with the defender.
I tried making a MC/TA controller, I wasnt feeling it, I've already used MC on my Mind/Elec dom, and permadom+Mind Control is nice, but I do love my TA/Arch defender, so I like both sets, but I'm only gonna re-visit one of them, so I'm gonna remake the Mind/TA into a Arc/mental Blaster, or a TA/Psi, the idea is that he's a psychically gifted person who was taught concentration and the like through archery, and as such, a way to control/focus his psychic powers. So, sell me on both combos.