One I idea had thought up is that everyone might have a "leadership class features"
How this works is quite simple. In each and every class, we add in an extra "class feature" that exists only under the perveiw of Leadership.
So for instance, rogues and classes that follow it might have an ability "theives guild" gained at... level 3 for rogues, 7 for Spelltheives, ect.
This means that, by virtue of "leadership class features", some classes might inherently have better aptitude in leading than others.
The exact nature and distribution is undefined and for the most part, dependant on what the system might look like later on, but martials should get more than spellcasters. Fighter in particular would get one at every level he doesn't get a feat, for instance. Wizard would get one every six levels in this scenario.
And, think about it. Charisma is important for leadership sure, but so are wisdom, and intelligence. Casters would inherently have better ability to apply leadership through raw attributes and direct power, yes, but they get less "perks" because of all their emphasis is placed in personal power and learning instead of leading and command most of the time.