Other than a more cool name, of course.
Being able to walk.
How fun would it be if you could walk around in Flight Form? Very! I imagine it would have to be something like getting close enough to the ground to where you "lock on" or whatever happens. You know, where only the spacebar will release you. Then you'd have to land, using either /sit or the 'X'-key (default key). And then you'd have to switch to walk mode instead (Num Lock by default). That would make the bird walk instead of fly when you start moving.
Switching back to run mode (Num Lock) would lift you up to the low altitude flight and so on.
Just a thought. I think it would be awesome if I could strut around in Shattrath, to the envy of every other class out there.
One can dream, right?