There are many good different kind of leaders, you have your delegators, motivators and micro managers. They all can be effective if they have the right council behind them and have the activity levels.
I really do think its being realistic about what you have in your tribe, over assuming ones ability will often leave a tribe exposed, it is rare to have a tribe that is all 'pro' so all of it is learning how to make the most of what you have. If you can make your bottom 1/3 of your tribe productive then you can all do well (easier said than done especially for grassroots)
The best tribes are the ones that require minimal influence from leadership & allow players to expand at their own quickened pace (ofc deadweight must be dropped). Tribes that "lead themselves" I guess you could say. I also believe the environment of the tribe is very important - leaders who run tribes without etiquette/behaviour/forum post limiting rules create much better tribes in my experience .... this is a war game for fun not sunday school - I don't need some power tripping divvy trying to control my every thought & action.
High activity. Communication with the tribe and ability to make compromises so that each member is looked after. Then on the diplomatic side knowing when to trust people and when to play your hand. Knowing when the time is to play a dirty card and how to ensure your tribe presents a positive image is essential. As well as ability to keep players motivated and recruit new co players when people need cos.