I felt the exact same way on my AST and I also leveled it after doing WHM. It just felt underwhelming to me.
I genuinely feel that it stayed that way pretty much until 70 but at 70 it's got a nice flow to it. The 40 second CD on ED is amazing and not to be understated and the regens you can put out on AST are also nice.
I think it's just that you get comfortable on WHM's plethora of oGCD options and AST doesn't stack up in that department.
I also agree with Taika - you aren't raiding on it right now, Aurum Vale doesn't have a hard enrage, I would just Bole the tank when they feel squishy. Also don't be afraid to Ewer yourself.