I think clan leaders should have their clan tag a bit differently to show that they are the leader of it. I think {ClanTag} for leaders and [ClanTag] for regular members would be a suitable change, and a small but excellent idea at that.

This can be considered as a decent and simple idea, making it more convenient for people to search for the leaders of several clans. Supported.

We were going to use this to distinguish unofficial clans from official clans.

I don't know why do you suggest this other than showing off your "position of power". A clan isn't about who is leading, it's about the group of people.

I like the idea too.
For unofficial clans can't you just do the (ClanName) and for official [ClanName]?

That's the plan.

i don't like the idea to show who are people in power. people will just start to suck up right people to get into clan instead of trying to communicate with all the members. we have no leaders for this very reason.

if you need to feel in power and you want people to suck up on you in a video games you have some serious mental or ego problems you should adress it to your therapist before it's too late.

OR!
Just do L[ behind the tag...

I have to agree that ranks matter. Leader: L[name] CoLeader: CL[name] ext. (add on to deak)

Prefixes could be handy despite the aesthetic cost. Most people don't care about ranks and would find the prefixes obnoxious. If it is important for whatever reason, they can check the clan page anyway. Though I would still consider implementing something similar to this, if the rank permissions gave access to various clan related commands ingame.

However, if you need a prefix on your clan tags just to know who your own leader is, then you have serious communication issues within your clan.