People have to merc en masse against for one reason: you're the biggest faction NA. You guys could, if you wanted (and I remember specifically a few battles early on where I was lucky to get in because you were actively trying to do this) fill your roster entirely with your own faction, even if only 1/3rd of your Strat members are actually active, seriously.
I know CHAOS can't do that or even half of that at most times, FIDLGB can't do that or even a quarter of that at ANY time, Teutonic can't do that, Hospitaller can't, FCC and Occitan might be able to do that (only at an extremely favorable time for either of them, really), and Fimbulvetr just barely could given absolutely perfect settings. I'm not saying this to call you a pooty or anything, also.
If your faction were broken into it's constituent parts on Strategus (The Kingdom of Veluca, Murder Boner, Hounds of Cthulu) as separate entities I know I'd be a lot more likely to apply for them in any given battle. Hell, I'm in a cRPG clan that has like, four of it's members in another separate Strategus clan (The Republic of Mates @ 9 members total). And those are people we could actually direly use to mount an offensive (we've had to settle for just giving them troops we couldn't use in exchange for gear).
Edit: typo!
Why would 3 seperate factions that are allied, be any different than 3 allied clans in one faction? We would just be the "Evil Bloc," or the "UIF," or some lame group that anders thought of while he was taking a shit. We don't have allies not in the faction, we like every other clan lobby our mercs in a way that gets us mercs in our battles. As of right now, we get about 60 applicants a primetime battle, with a dozen or so of those being below 27.
And mala, you give me wet dreams at night, but this small clan v small clan utopia thingy you guys believe in is what ruins strategus. You guys rarely fight any battles, and yeah, its easy for your members to get the xp from all the battles because your mercs are damn good. But no clan not in our faction wants to hire DickSwag_Recruit_of_TKoV to a battle, because hes probably going to go 3-42.
It takes almost a minute to scroll down our battle results page, and we usually bring 5-10 big battles a week to all the members in our 3 clans, and the rest of the community, and have lots of fun doing it.
Without some sort of institutional overlord, physically making clans fight eachother in fair, even wars, their will never be a "fair" war in strategus. And at that point, its no longer something I personally want to play.