When did they decide to make Hook Horrors look like Skekzis from the Dark Crystal?

I remember the old fiend folio image .... huge hulking ....

Yep I know and i'm with you there big time. Those old 2E Fiend Folios always did do a great job with the monster illustrations and I think they truly put the 'Horror' in Hook Horror with the old pics. The IWD2 version, which to say I wasn't impressed with, took alot away from what Hook Horrors actually are.
That said, I think this is one of very few flaws in the game.

I dunno, I think they look more like what I understood hook horrors to look like. A mutagenic vulture-crab. ;) The skinnyness of arms and the like is fine, but the body is a BIT stouter I understood.

Well.......... I don't know bout you guys but I definitely lyk what they did to those monsters, very unique. But I dont lyk fighting them, they come in waves (in the river caves) from the front and back totally trapping my troop.

I wonder where they get those ideas.....

True enough! Again Animate Dead to save the day (if only to protect my wizards that are *constantly* targeted by those bastards)!