I've never ever had a ghul stun me, and I've only played ADOM 1.1.1, so I guess I have the advantage of clear memories on that. I guess the stunning has been replaced with the paralyzing.
PS: Okay, I should be honest, the first version of ADOM I've played had no talents, so that probably was 1.0.0... I'm still positive that ghuls do not have stunning attacks anymore, though, beyond the ability of every monster to stun you by taking away nearly all your HPs.