I get the "vibe" that he's decent at those last 4 though not necessarily outstanding. Communication is the thing we see least. The others I think we have seen some evidence.It's not that there's a case against McLean's leadership potential. I'm just not really sure what the case for it is.
Take that piece you linked, which was an interesting read. I think we can say with reasonable confidence that McLean checks only one of those five boxes. That being passion & commitment, from all accounts (Dermott Brereton right through to Horse & co's words on him. His journey onto an AFL list is itself a testament to that.)
The rest - how effective he is at communicating, how positive his attitude is, how self and socially-aware he is - is really just guesswork from our vantage point, not being within the four walls of the club or knowing the guy personally.
I'm not pushing his trolley as a captain and with two or three captains I'm not in favour of vice captains but I think he could be a good addition to the leadership group, depending on who else there is.