Vault breaker + dark passage + flash = falcon pawnnnnnch from down the lane lol

i thought he was talking about kassadin for a sec lol

To Op:

You arent taking in count that Dar Passage transport the ally towards you, and to use effectibly Thresh could need to be away of the teamfight for it to be effective, making the rest of his kit become useless in the meantime. DP could be more effectibly used in escapes when an ally is traped and flash is on CD, Thresh can pull them to him. OR to bait, or better position tanks lika Amumu or Galio. Plus, I think that your allies cant right click itthe lamp if they are stunned/rooted/suppresed, so it still DOESNT counter Blitzcrank, since the grab stuns AND is follow by a knock-up, not counting other ccs from enemy team. Its less OP that many think.

Can Thresh perform other actions while the lantern is out? Or is he just waiting there doing nothing but waiting for an ally to click it?

provided amumu plays with the team.... or galio but even then if u have half a brain and shutdown the enemy adc/apc before amumu and thresh can pull off their combo this is effectively moot... not to mention we have to assume thresh doesn't get focused and utterly shutdown or is low and has to retreat.... Of course taking this from a standpoint of sorts it can be a little annoying but far from op... its no worse than a ghost flash combo or an ezreal shift/ flash combo .... in terms of escapes