His early/mid game is unbelievable and often led to a prompt surrender or fed hard so his late game is superior against their ADC. Will have a tough time against an equally fed ADC as I'm aware his range is incredibly short and his skills still focus on support. (Hate me for saying it, but an ADC that can also support works as two champions if played by a highly skilled summoner.
Easy CS'ing, HUGE poke, awesome finisher with Hook/E.
AD stacking has gotten me first hits for 2.3k on minions, and 1.5k on champs (Magic + Physical crit), that still hit for 500-1000 depending on enemy armor. And can easily one shot squishies late game (Think of Veigars ult on a 8-10 second Cooldown)
Pair with a poke/stun support and harassing is ridiculously easy.

Runes: AD Quints, AD Marks, Armor Seals, Scaling MR glyphs
Masteries: 22 - 7 - 1 (AS, AD, Armor Pen, HP regen, MR, -15secs on Flash)
Skills: Q,E,Q,W,Q,R,Q,Q,E,E,R,E,E,W,W,*R,W,W
Items: STACK AD!!!!!!!
Vampiric Scepter (or rush BF sword first)
Greaves or Swiftness (chasing builds your Q so that last hit will be massive) ((NEVER chase too far))
BT
BT or IE
PD
...at this point you should build what is needed that match.
Owning? Another BT, Runaans
Dying? Mallet, GA
Get FB, WARD, become kill lane.

HARVEST, HARVEST, HARVEST SOULS. Regularly getting 150+ armor by 30 minutes.
Dying to AP? Get MR items, or ask support to get MR auras.


33 minute game I played in ranked solo (Meanwhile in Bronze IV, because FML) were I still carried and was playing fairly poorly.
Thresh just came out, I don't have him mastered by any means. You will be made aware of that when you see how often I **** up my E
https://www.youtube.com/watch?v=AiMM...251nnQ&index=1

It kind of reminds me of Taric, although its rare, sometimes you can see him stacking attack damage. It does not mean he is not useful this way, its actually an effective way at times to confuse the enemy team, kinda like attack speed Lulu. It can work, but sometimes you may get countered hard since you are kinda stepping out of your ordinary bounds. Of course, I have not tried Thresh at all, so I really have no idea, but it sounds viable. Considering he is kinda tanky and gets free bonuses from souls.

bump

Thresh+Blitz Combo?

No armor pen whatsoever in your build? Good luck haha

Thresh's kit works really bad with ADC.

Thresh's passive gives AP. This does not benefit him AD whatsoever. Don't argue that it gives him more damage, because then I'll toss AD Veigar in your face and let you choke on it.

His Q's passive, though scaling very nicely with AD, mathematically will deal 200% of his AD per 10 seconds. That's 2 extra attacks that don't benefit from Crit, get no bonus from Attack Speed, and aren't affected by Armor Pen or Lifesteal. The strength of ADC is that they have so many stats to build into, and they multiply together when you get a bit of each.

tangent: That said, he can be played easily as a tanky ranged AD bruiser because he doesn't need to constantly attack to deal damage with this ability. It would only require slight tweaking of your build to turn him into this.

Q's active requires you to either pull yourself to the enemy or not attack for 1.5 seconds. Either you put yourself in danger or don't do what ADCs are supposed to do. Attack. It also does no damage because you're building AD.

W's shield is going to be worthless, otherwise nothing notably different from AP or other Thresh. Generally utility anyway.

E has a casting time comparable to Caitlyn's Q, except it doesnt scale off of AD. Thresh COULD mini-peel off of himself with this ability, but it has pretty short range and knockback for a peel. You'd be better off playing Tristana.

His ultimate would be useful as an area deny, but Thresh can do that regardless (and so can AD Veigar except Veigar's has range and is a stun). ADC Thresh has to stay in the back lines so it wouldn't even see much use. AP or Tanky could jump in the enemy team and just toss it out. It would even do damage.

tl;dr
Thresh ADC = bad.
Thresh AD Tanky Bruiser = good.