I'd agree that as many of those extra mounts as possible be moved off of your action bars to make way for the essential skills. I'm not sure how many heavily-used combat skills mages have, but as a rogue I can get by with 2 1/2, 3 tops if I throw in some situational macros. That would give you a lot more free space on the bottom of the screen.
Professions, portals, hearthstones, mounts, raid mats except for potions, etc. can be consolidated on those right-side bars that are more out-of-the-way. You've already got a good thing going there but some more stuff could be shifted over if some mounts are removed.
It wouldn't give you a whole lot, but you could collapse the five-bag display into the main bag button and move it to the left of your other menu bar. Allows a bit more vertical room on the right.
For reference, this is what I'm usually looking at. (Stuff being toward the middle of the screen is because I've found it's one of the only ways I pay attention to it enough. That's optional.)
http://imgur.com/a/IHgxJ