One of the biggest "griefs" many of the people that I play with is the ease at which someone can make a set of 'floating' stairs to get over the walls that took days if not weeks to construct. Granted a pile of crates or stacked logs can get you over a wall, but if the game mechanics made those items Gravitational, they could not 'float', and thus would make getting over a wall much harder, giving both realism, and balance to the game.
Right now Server Admins make rules for raiding that prohibit these kind of 'cheats', but it's very hard to enforce, and players feel jipped. Is it going to be so easy to compromise walls in the MMO as well??
-Mourdeeb-