Taric's Q costs too much mana

Its fine. It balances because of the passive with AA.

Another thing to point out is the heal does not go up,just the charges. most people just put 2 levels so after every ability you get 2 charges and heal. though eventually once late game comes leveling it up is more of a hinderance due to the mana use going up and the extra charges from 3-5 not being used too frequently. you could store you heal and use another ability but even then, the heal being level 5 STILL makes maxing it a hinderance to your mana consumption in most cases.

that's why i max w first and q second because by the time i max it out his mana regen covers for it

It is better than it was before. Q has a shorter Cool down but W is more mana efficient. Q is best used sparingly at max charge.

http://www.auplod.com/u/pdolua802d6.png

The problem with Taric's Q is that ultimately it's not a thing with much innate gameplay, as it's designed as a spammable heal that is pretty much guaranteed to affect one other player. There's some gameplay around grouping near more allies to heal them too, but in the laning phase, it's this super-reliable heal, and since healing in the laning phase mostly just negates plays over time, ranking it up needs to be gated pretty heavily.

While the mana cost for his Q is prohibitively high, the issue with buffing his heal in any way right now, whether by lowering its cost or increasing its power, is that it would cause Taric to heal too consistently in lane, simply because of how it's built. I feel his heal could stand to be a lot more powerful if it were made more dependent upon him actively committing to fights, such as by activating automatically upon autoattacking a champion or monster. It could potentially allow him to trade much better, too, and use his persistent healing in protracted duels without having to consume tons of mana.