Because he can put out loads of dmg and help jungler gank with W. He could easily pick up a crazy garen tower diving you by ultimating him + exhaust. Very nice damage output because of his Q stacking with AD. With this build you will be taking down pretty much anyone who tries to stop your farm if it's not a gank of course.

Okey so, (Q) Thresh's Death Sentence passive does stack with how much base damage he has. It's so good that when you hit level 9 and have Death Sentence maxed you have 200% more damage on an auto attack. Depending on how much magic resist your opponent has of course.FOR GANKING: As Thresh is such a new champion you should tell your jungler that you will be putting out your lantern for him which is why you take it at level 2 for early gank and that he should click it to get dragged to you. I think most junglers doesn't know that 1 day after release on this new champ. At level 2 you could easily pick up first blood but... You will need too hit your Q succesfully on enemy and in most cases it will be a very nice first 90% if you hit Q blood but, as said this is for when your jungler ganks. Thresh's passive is soo op! It gives you ability power which could be nice as all your spells stack for it. But the main thing imo is the armor that it grants you. Adds so much survivability vs AD based champions like GP , Fiora etc. A very good passive . Will get nerfed. He's E is just helpful for farming, escaping ganks, picking up kills and ****. His ulti just has massive CC and lots of damage. Very very good for escaping . And securing kills with like 90%. If your team thinks that you are trolling which probably wont happen but it happened too me once because i only play ranked games at 1200elo (sucks i know that). But still just get top lane and you will mash everything with this build. You will have a good time farming and winning lane. Any Champion that counters Thresh would be like the same champions that counters Jayce or someone ranged top. I will not add that to the build now so you have too check that yourself or just learn. But enjoy this build. You'll have a gooooood timeee...!