With the increase to damage from siege, siege rams are nearly useless.. they break down extremely fast and give little to no protection whatsoever to the people driving the ram.. which means you're much better off NOT using a ram to take a keep.
Maybe the rams should get some boosts / tweaks to protect the people driving them (ie. like it was in DAoC, where people on the ram got a reduction to incoming damage).. and the ram could use a boost to hit points before breaking down.
Taking down a gate should be easier than taking down an entire wall, should it not?