Thresh is a problem? Maybe.

The addition of Thresh has caused the Triumverate of Supports Poke > Engage > Sustain > Poke etc. To shift to Engage> All. When all the other Supports were nerfed (something that still confuses me to this day) Thresh was untouched. He was strong ever since he came out, but the problem is that he isn't him being Overpowered, because he isn't. The issue with Thresh is that he changed the meta of supports to be centered around him. He has everything, even sustain thanks to so the argument that he misses ONE mechanic isn't even valid.

CC? Effectivley 5 seconds with his Q lasting 2 seconds before he jumps, the E being not only a displaced but slowed for an extra second and finally his ult which is a 99% slow for 2 seconds. While there's nothing wrong with having a lot of sustained CC, Thresh doesn't pay heavily for it. His Q also reduces times when landed and he can choose wether he go's in or not. His W is cool, on it's own. I like it because it's his unique thing. His E has a passive of Collected souls plus 80 / 110 / 140 / 170 / 200% AD which secures poke, which is better than a lot of other Poke Supports. His auto attacks are Non Projectile, Melee-Ranged attacks which can pierce Yasuo's wind wall and Braums Shield. His basic attack wind up is also only reduced by 0.25% per 1% attack speed, rather than the standard 1%. As in standard for all champs, not just supports. A weird mechanic to have on a support which is cool, but combined with his enhanced autos from his E adds less Risk and only brings advantages. His passive (the one that is actually a passive) is fine to me, it's quite cool and interesting and has a payoff of no armour per level. His mana costs are only relevant if you spam his abilities, otherwise mana is not really a gating on his kit. The problem is that Thresh just gives so much compared to other supports. Compared to someone like Sona. Sona has her Q for poke. It has pretty good AP scaling, in fact the only really good scaling on her kit, with good bases it is what most Sona's max first. Sona's W is a heal with meh scaling. At 30% scaling max healing with a temporary 20% Shield it does have a spot, but it isn't really the best. Especially if you don't build a lot of ap, instead more Supporty like and and it's mana costs cause her to pay for her sustain, so you have to think about when to use it. Sona's E is a move speed buff 13 / 14 / 15 / 16 / 17% (+ 7.5% per 100 AP) (+ 2% x Ulti Rank) for herself while 10 / 11 / 12 / 13 / 14% (+ 3.5% per 100 AP) (+ 2% x Ulti Rank) for allies. Not really the greates movespeed buff. Rather it is the weakest spell and is mostly used to speed yourself up slightly and build her passive. Her passive of course is the Three spell auto attack bonus, meaning you have to use mana for the auto enhance. The Q-Passive auto is used the most, with a bonus 40% damage, causing Sona to be played in Mid lane a lot as it is quite a lot damage. W-Passive also reduce the target's damage output by 20% (+ 2% per 100 AP) for a few seconds. It is useful for teamfights if there is a very dangerous assassin. That is if you can auto them and get out to avoid the rest of the team as Sona has all her abilities but remains squishy. E-Passive is a slow of 40% (+ 4% per 100 AP) for 2 seconds, which is underrated for how good it is. Finally there's her Ult which is the line stun, which costs 100 mana, stuns for 1 second and has an 100 second cooldown at max rank, meaning a 60 second cd with max cdr. See, Sona isn't weak, she's in a fairly good spot right now I'd say. Maybe she could be a little bit stronger but this is where Thresh comes in. Thresh has low mana costs compared to Sona, Nami, Lulu etc. He is also tanky, builds tank and has High base damage with alright ap scaling, and further scaling on some abilities. He also beats all of them in a skill vacuum. Some may have advantages in lane but they do not offer to the team what Thresh offers. Thresh offers +Soft CC +Hard CC +Displacment +A unique Escape +More options for Tankiness with higher base defensives (6.9 health regen, 30 MR) and health (2074 base health at 18) (no armour per level but his passive can grant more armour than some champs armour per level. Especially if he is present around Champ kills) +Can build full support and retains his tankiness. +Slight poke, a noticable amount of damage +Strong teamfight presence What Thresh doesn't offer -Heavy Sustain -Good Shielding

Personally, I feel that a lot of other existant supports should be brought to Thresh's level. Nerfing him too much would just be pointless as it would just make one champ weaker while keeping relevant and other supports less so. But I feel there should be more tradeoffs for picking Thresh over say, Taric in some situations. Thresh is not a Jack of all trades- master of none. He is in fact a Jack of all Trades, master of all. I feel that other supports need to be buffed, I'm not sure how, but done so appropriatley.