It is written that the hell bind (feoh immobilize skill) casting time is 2 seconds, which would make it as fast as elemental spike or aqua crash or speed burst, but is much slower. In fact, its slower than devils curse, which has cast time of 4 sec (as written). Whats up with that?
This(and mass one) skill has fixed reuse/casting time like a rebirth. Yeah it is sad, but NCSoft dont love feohs, so hell bindings from Agu are much better, than from skill.
Feoh skills design is simply horrible since Feoh was introduced after GoD . Look at skill Air rider ? Just LOL . You cannot even use it properly in PvP. Any hit ranged or close cancels it + when you get hit IT stops your toon completely. Which makes it even worse :D. As you mentioned hell binding cast times is simply ridiculous. Youl will kill you 3 times while you cast it :D or you get 5 backstabs while you cast it :D so yah be carefull with those lol.