Personally i think that the new "Faction" will be exactly what many have said. Mercenaries.
Easeist way to implement 6 new heroes. Roman and Ninja would definately fit into it, you could have just class called the Gladiator. What would be cool is if you could interchange thier weaponry. Sword+shield, 2 sword, 2handed maul etc. Your weapon drops could be random or you basically have untill your first prestige to choose your calling. I could see a Pirate or Swashbuckler class Cutlass and dagger or pistol-knife where you would unlock a pistol shot as a feat simlar to Valkyrie or orochi.
What would be intereating would be if they could add in a Monk. Hand to hand. Your weapon drops would be hand wraps or gloves etc. That would be interesting to see animated.
Honestly i would love to see new factions but im hoping this game kinda stays as is with new heros being mercs and if you wanted more factions, wait for FH2 and do it ALOT better now that you know what is and isnt working and put a programming base that would allow for up to 10 factions or whatever. Personally id love a more fantasy oriented theme, ie Dwarves, Elves, Humans, Orcs, Trolls, Goblins etc. Be awesome to actually play a game where i get to be a hardnosed dwarf warrior with battle axe and shield fightin one of them "prissy little elves jumpin an dancin about". I could really see a HUGE variety of heroes/toons being implemented.
Its a game after all. You want historically accurate, go take university history. Me, im all for entertainment. Hell add Monsters as a faction and include small dragons, young giants and creatures from the infinite layers of the abyss for all i care. If its fun ill enjoy it.
Like this game. When i DO get to play, i have fun mostly. I enjoy being beat cus i know i zigged when i should have zagged. I enjoy winning when i know i actually OUTPLAYED my opponent and didnt spam the ****** moves. This game is fun for me. Am i the best? No. Simply put. Have i played enough to be a decent challenge, i think so. I know when im outclassed and i know when im being zerged by someone who only knows 3 moves. I dueled a person a few nights ago probably 20 times in a row, i think i won maybe 5 rounds out of the whole thing.. maybe 6 but i had a HELL of a good time cus this guy was actually a good player who i was determined to out play. I did 5 or 6 times out of 20 but it was one of the best nights i had playing this game cus there wasnt any GB spamming or cliff tossing(on purpose). Just 2 hours of fun.
Anyways i went WAY off topic, so yeah. uhhh Mercenaries. Yes i agree.
PS The persons name was Merasmus_1000 i think on Xbox one. Just sayin if he reads this, props to you bud for an awesome time. If you know the guy, then lucky you as hes one of select group of people i think who really enjoy the game for what it is.