I mained both old Taric and the new one and reached plat last season by playing only him so let me share my thoughts.
Taric's rework was nether good or bad, imo they shifted to much of his identity both lore-wise and gameplay-wise.
I wont go into details about his lore here but its shame he got shoved into Targon "because yes" and left there without actual connections to anyone.
As for his gameplay side, he went from unique playstyle of frontline enchanter-juggernaut with auras (slow but powerful both in lane and teamfights) to somewhat tankier Janna (shield/heal stunbot that is doing his job from afar).
Riot states that he is now enchaner/warden subbclass and thats a problem - as a defensive enchanter he is much weaker than someone like Janna and as a warden he is beaten by Braum.
I feel like with his rework Riot tried to create as fair kit as possible - everything is delayed and telegraphed - in game that is filled with mobility and unfair moves...
It also forces Riot to balance him around his best case scenario (no matter how unlikely it is) - 5man ult, 5man stun, 5man heal - so he will never again be strong on his own.
As for his new ult... I hate this spell. Yes, its powerful and can turn teamfight upside down but also takes alot of his powerbudget and often ends like "fire and pray for best result" because your own team can run away from it :D and in high elo none will waste a cooldown if Taric's ult is up.
His mana costs are very high and he has T H E W O R S T mana regen at lvl 1 in entire game (its more that 2 times less than other enchanters).
His tankyness went down and it feels like Riot left his armor scaling as a cruel joke because he cant even build enough armor with current meta support items.
So yeah thats it...
I guess i will still main him and pray for a better day :D.