Would be cool, especially if you added "heroes" like in Star Wars battlefront.
Would love to play this, based in Westeros, with a TON of factions, and the faction war actually meaning something. You could even implement "super moves" of sort, where a match would go into a cinematic cutscene if one of the heroes activated their "super ability"
For example:
Daenerys, flying overhead on Dragon, just lighting up the battlefield.
John Snow summoning Ghost,a nd having him wreck carnage besides him
Arya morphing into an enemy faction skin, and getting 1 free assassination (one shot) kill.
I could go on and on. You could even utilize the same mechanics, and change a few maps.
I think this game would sell crazily, and you should really look into it!