in terms of naturalness, probably ENTJs take to it more readily.

however, INTJs can also make good leaders, BUT we don't tend to want to be. in fact, we'd rather there was someone else around who can do the job. but if there isn't, we would do it.

i never led anything in school, and only in my senior years in university did i find myself in the position of having to take leadership of groups. now i notice i always end up being some sort of leader in something, despite assiduously trying to avoid it. in all cases it is the group who makes me the leader either formally or informally.

my personal opinion is that when an INTJ leads, he/she does not lead with charm. he/she leads with trust. this is why INTJs don't tend to be first choice - it takes a while to build trust. it helps, of course, if you have both... but then again INTJs don't WANT the leadership position in the first place, so....

i agree that it can be difficult for an INTJ in top management positions to penetrate the layers of middle management. but, one way to do it is to find a competent person of a suitable type who can do this.