This is an interface for you who does not appreciate a bottom UI, it is first and foremost for tanks, with high priority given to the target, and target data, and not very friendly for other roles.
Tested with Assassin and Juggernaut, both have given me no problems managing cooldown, target priority etc.
All abilities placed to the left with a medium "ability" window and a large "cooldown" window, for the damage reduction and crowd control abilties. One very small button window for non-combat abilities, and one slightly larget for commands rarely in use.
More buttons are available, if you would so require.
Slight alterations will be made to make it seem more seamless.