Main blitz plat 1 here.
Blitz is kind of brain dead champ. Beside his hook he is useless. His kit is worse than any other support champ. And in this damage meta he is falling behind because pulling isnt enough anymore, you need to deal some pretty good damage if you want to take the kill (talking for 2v2 situation which is bot). In TF pulling is crucial but really depends on the situation. If enemy team is ahead and you do the pull... it can cost you the game because now there are many mobile champs that will compensate the disadvantage you created. In TF most usefull thing is his ult because it has silence, thats it.
For example vs other hook supports:
Blitz -> best disposition hook, has passive shield, low damage, silence on ulti, low time CC
Thresh -> monster CC time , can set up ganks with W + shield ally, damage as blitz, mass slow R
Pyke -> better damage, monster mobility, can share gold, health regen from grey health, CC time like blitz (higher with lethality on E )
Naut -> better damage, monster CC time, have escape tool, shield, mass slow E
So skilled players will always choose the champ which will be more complex and can bring more. Blitz is a one trick pony :) + 100 range doesnt change much.