I guess the question with these sorts of mechanics is how abstract are you making the game? I mean, its a class feature, right? That means you PRETTY MUCH have to accept that it can't be subject to 'fictional positioning' considerations, to put it in terms that Pemerton would probably use.
I'm fine with getting really, really abstract, as I feel D&D has always been there in a lotta ways.
I do like the idea of such a character milking the old 'training the villagers to defend themselves' (and getting them all killed in the process, but somehow, you're still the hero) trope. When the BBEG has a small population that's opposed to it, oppressed by it, loyal to it only out of fear or the like, that's an opportunity for some fairly good fiction, that, in most RPGs, ruins the actual flow of play, by adding too many DM-controlled creatures to combats, creating logistical logjams, stealing the heroes' thunder, and the like (getting innocents masacred). If that fun bit of RP gets you allies that can be abstracted into a useful - but not OP - power in some battles, though, that's fine.
My point is, I'd rather have rules that allow a 'warlord' to gain all sorts of crazy advantages when commanding 'minions', but leave the actual mechanics of such minions (hirelings in 4e terminology) up to the normal hireling rules. Thus a fighter or wizard could easily hire a couple 'archers' to follow him around and provide added firepower, but if they were commanded by a WARLORD (with the right options I suppose) then they'd be much more powerful. Admittedly that's allowing for circumstances to be created by the GM which might make your character unable to perform some function he has, but there are answers to that (IE get some magic which allows the production of instant minions, plan carefully, make sure you have alternative powers/targets for your effects, etc.).
One way to handle it that I'd considered for the Controller take on the Warlord was a fairly simple mechanical distinction. When a Leader Warlord gives 'commands' and tactical advice and the like, the player or DM (if the target is the NPC) make the rolls using their stats, if the Controller Warlord does the same, he makes a check using his powers - the allies are just fulfilling his Requirements line.
Edit: Another thought, to enable highly situational powers without going the whole ritual/practices route and making it about gp/surge resource management, would be to have powers that have an additional or different effect, either explicitly or as a consequence of how they're written, when the situation comes up. In this case, that'd mean a power that works in a Leaderly way when only PC allies are available, but in a Controllery way when a swarm/mob/throng - formation - of temporary allies is available.