the biggest problem is level design. there are many maps that suck overall and some of them would suck probably even more with ladders. but its not the ladders, its the maps. with good maps battles with ladders can be better fun.
the way i see it the correct level design should offer you various options for reaching some places at a trade of for something else - for example i'm not against some tall tower in the middle of a map from where you will see everybody - if the tower will be narrow without a cover (so if more archers stack there, they will be safe against cavalry but very vulnerable to other ranged as they couldn't maneuver there). there can be "better" roofs at your spawn, but then you won't probably be able to shoot to the places where the action is (in the middle) etc.
problems are roofs that offer perfect cover for archers from both cavalry and ranged (when you're able to hide behind the roof) that are on sweet spots.
also with slot system, not everybody can really afford a ladder. also ranged is not what it used to be, sniping on a distance is no longer an option, you can't hit a shit even with 170 wpf above 30m.
edit:
i'd also bring firebombs back to c-rpg
1 slost, lighter, otherwise same as before.
throw it to the roof, watch the unaware archers BURN
sounds just awesome to me...
kicking the smoking firebomb would douse it.