Loved the game 1-70, but 70-75 is the most painful gaming experience I've had.
They have changed game-play dramatically. Where it used to be relaxing to play, now it's just frustration. Those who like playing in the Tolkien world for challenge rather than story might love the changes. Also, the heavy armor classes won't have as much of an issue.
The expansion is extremely buggy with some areas such as the Pit of Iron being completely unplayable. You keep falling through the world or crashing or getting stuck in combat at MANY points of the zone. Almost every ramp (and there are a lot) has at least one "hole" in it.
Most of the time you will only have one active quest and will end up doing dailies to get to 75 since you will run out of normal quests.
I would avoid playing a Rune Keeper (Rune Kiter now) unless you're always playing with a friend.
I will greatly miss this game, but SWTOR is right around the corner and hopefully it will fill the gap. But it's no replacement =(