The allegations I've seen floating around is that he deliberately withheld certain types of leaks. Thereby making Wikileaks no longer neutral, but politically-motivated.
> Is it not enough that one state committed a crime and he reported it?
It depends on what "it" would be enough for... but if he indeed actively surpressed damaging info leaked to him on par with the stuff he has released, yeah, that makes matters complex.
Another criticism I've seen is that the leaks did not do any redaction whatsoever - even when it clearly pertained to informants in war zones. For that, if the allegations are true, my view is simple: you shouldn't do that. And if you set up an infrastructure for leaking, it is reasonable to assume that you're capable of handling such an important and obviously necessary step.
So "isn't it enough?" - no, it is more complicated than that.