Rework his passive. His kit is fine the way it is but his passive as a support is useless for the most part. Can we get his basic attacks to increase mana regen for a short duration like fiora's with health regen? I think that would be pretty sweet

Nah, his passive is strong enough for a support. It'd be fun to get more mana out of it, but it's already not hard to moderate his ability use to keep his mana up.

slam that turret like no tomorow, free mana

You can help your AD carry farm by staggering the health of some of the creeps. If two are dying at the same rate hit one (before it would be a last hit for you) and then your AD carry gets both.

Passive is op on ad taric. Call me a troll as i get CHUNKS of mana back per auto attack.

I'd actually agree with this for a completely different reason. It needs to be reworked because it only works out if your lane is doing well. If you're desperately trying to keep the lane not pushed, auto attacking minions is not conducive to this. It is wonderful in all other situations of course! It would just be nicer if it was better adjusted for more.