Do you really want to add another mechanics into already overloaded with tons of mechanics kit? Thresh is the most overloaded and most overpowered support when it comes to what he can provide for his adc. Since his release, he still remains the most popular support and everybody can clearly see why. The only thing he doesn't provide to his adc is heal, other than that he can do just everything: pick targets, peel, get someone out of bad situation with lantern, provide a shield with his lantern, help his adc gap close with a lantern, he has very strong poke from E passive, and uses it's active to either push someone into your adc or away from your adc. Hell, he is even quite good at initiating team fights. I know, he's not the best in all of the things I just pointed out, but no other support is so versatile. Whenever you pick any support besides Thresh, you know you are going to lack something that can be very usefull. You pick Janna for peel and disengage, Blitz for picking targets, Alistar or Leona for teamfight engage. But Thresh? Yeah, his hook isn't as strong as Blitz's, yeah, he doesn't peel as good as Janna, he isn't either as good initiator as Leona or Alistar. But he provides all of this, not as just a crappy version of what supports mentioned above provide, because all of his skills are very, very strong. A lot of people will tell you: even if Riot decided to nerf his base ad to 20 at lvl 1, make all of his abilities base damage below 100, his ratios lower than 0.5, Thresh still would be picked.