Think of it this way.
We start off as with the mounts weaker, then slowly, they are able to become stronger if we chose.
Which is what Neji tried to do with the specialties & look what happened? Players complaint & voted the old specialty system back.
I looked back, and he never said that the specilities would be able to become stronger in the new system than in the old system, or if he did, he didn't make it clear.
People noticed that their justus got a lot weaker, and complained about that.
However, he probably should've at least touched on the fact that they could've been stronger.
Besides, he has been thinking of messing with the mount system for a while.