Ok so I understand there will be mercenaries in DoF, but what I would like to know is how do you recruit them. Are they at the local tavern, do you do so from your castle.. Personally I think it would be awesome to treat them like Knights of Honor (KoH) did and have them on the map.. You moved a general to them and were able to recruit from there.. They would randomly appear so you never knew where they'd be or what would be there unless you went looking for them. (You could even have npc mercenary armies randomly roaming around attacking & looting wherever they go.. Would give players another threat they had to be prepared for as they could appear at any time, but at the same time you could recieve a bonuses for accepting quests to go out and destroy them)
Also (& this ties into the above idea..) what about invasions.. were talking ones so large no single person or two could stop.. You would need a joint effort my a group of players or even guilds to defeat.. If it fails areas of the map could fall under control / have to pay a tribute to the invaders for a short while as a penalty.. If they win they recieve a nice reward
Lastly.. what about creating dueling option for battles.. where at any time during a battle the two sides can agree to a cease fire and can send forth a hero/their hero to have a duel.. The outcome of the duel deciding the rest of the battle.. This would be a way of saving a long drawn out battle or a way of ending one that has already taken awhile or has reached a stalemate.