So i was talking with my mates and in these types of games set in mid evil times there is never a drawbridge or a mote! so after you castle gets to lvl 31 why not extend new buildings to lvl 40 .... the mote adds a huge defence to the castle as does the drawbridge or a keep building... a way for the attacker to counter this is to have siege engines like a tower and battering ram that you can build in the workshop.... or you could even add to the hero the ability to ride a steed or something to increase the troops attack ability.... also with the walls you could add the ability to have towers and lvl the towers up... I also feel this game is very attack sided and doesn't offer enough ability to defend adding some of these ideas might not be a bad way to counter... after all in mid evil times castles were defended by far fewer men than the attackers :d hope these ideas might see the light of day especially the motes and drawbridges or towers for defence improvements... or add them as techs too or both ...