And as such this begins with the same intro, with the most important thing to consider when thinking about a champion.
As with any champion design, the most important thing about them is their "Power Fantasy".
The Power Fantasy defines everything there is to know about a champion from both lore and gameplay perspective. For example Orianna is a dancer by nature, performing a constant tango between her and her ball. Draven is a showoff who loves to stand out and perform for the crowd. Sion is a gargantuan undead warlord who shakes the very ground under his assault. Jinx is a mayhem sowing excitement lover who blows up things for fun before speeding away chasing the next thrill. Etc. And every champion has one.
When a champion really makes you go "Wow..." and takes your breath away, it's pretty much always because they have a power fantasy which matches what you personally like.
When it comes to Taric, there is really only one Power Fantasy which he fulfills. And that is Paladin. Taric is a heavily armored bulky healer. While Galio becomes a better mage as he gets tankier, Taric becomes a better support.
Taric's current issues with his kit mean than he has difficulty becoming good. A lot of his power is delayed behind his sluggish auto attacks, for reference Taric has actually got some amazing damage values against a target which is standing still, however he needs to space out his his passive to make use of them and his stun only lasts for so long, in between cast animations and an incredibly clunky attack animation the target he wants to beat up will run away before he gets his second passive proc off. And don't get me started on his optimal skill combo.
And thankfully something Riot recently did opens the perfect solution, the creation of a new role in League of Legends (or at least the new term for a role, before they were only referred to as "bad bruisers"). Juggernauts.
The official juggernauts so far are Darius, Garen, Skarner, Mordekaiser and new girl Illaoi. However there are many more as well, the likes of Tahm Kench, Nasus, Volibear, etc. also share many traits of the Juggernauts too.
Juggernauts were created with their weaknesses in mind BEFORE their strengths. In fact whether a champion is a Juggernaut or not is defined entirely BY their weaknesses. Some build mostly AD, Some build mostly AP, some build mostly tank, some even can build support. But they're all slow moving, they're short ranged, they're easily kitable... but that's OK. Juggernauts don't care. For them it's more of a case of "Your deadly skill is running away? Mine is making you wish you could run faster."
And that's exactly how Taric is supposed to be. What if Taric didn't lose these weaknesses and instead embraced them? The only difference is that normal Juggernauts bring heaps of pain to those which find themselves in their danger zone, Taric would instead bring heaps of disruption. With pronounced weaknesses, Taric's strengths can truly shine for what they are. He may be slow, but if he ever manages to wander close then the enemy is truly truly fucked.
(And if there's one thing I learned while doing research for this... it's that Taric doesn't actually know squat about the spiritual purposes of gemstones. I didn't find any sources at all which said anything like what he talks about. Emerald is not for insight, it's for hope and recovery. Ruby is not for vigor, it's for love and protection. And Opal is the polar opposite to Harmony, it's known as the king of jewels because of its marbled effect making it look like it's made up of lots of different other jemstones, it's known for bringing conquest and victory. He did get "Sapphire for Divinity." right though.)
The absolute main thing I tried to do with this kit is to make his abilities actually work for an immobile champion and also to improve their usability too.
He can now entrench himself in an area and be difficult to shift. He isn't designed to go chasing after people unless the situation calls for it with Crystal March and Amethyst's area, and they only give him a pretty minor boost in that regard. The main use of that ability is to resist stuns, slows and snares which would bog him down.
Instead of Taric's ability combo going: Do this, and then do this, and then do this, and then do this.... etc. It is now designed to fit together like a jigsaw. With the gem created by Shatter being on a longish delay he can now ult in between his casts to still get the bonus of the AP.