But they shouldn't be able to itemize CDR so easily with ghostblade and cleaver.
I'm going to have to disagree with you on the cleaver part, and probably with ghostblade too. I'm fine with ghostblade being a primary assassin item, like
is to some AP assassins, but cleaver... isn't really an assassin item. It's a bruiser item, and it's certainly useful on AD assassins, but it's kind of like a reverse (not AD version, reverse) zhonyas. Or maybe some hybrid of Athenes and Zhonyas, but AD. Eh, whatever.
My point being, I disagree with you. I think it's fine that ghostblade offers what it does due to being a primary assassin item, and I think cleaver is fine in this situation as well. Mostly opinion, to be honest.
Although, I think the real problem here and I'm not sure it's a problem, but if it is, is cleaver rather than assassin itemization. I suggest talking about that item further, because I don't think the problem is with ghostblade or assassins in general. The item is just too good on several assassins and bruisers, like an overtuned zhonyas or something.