I dunno...

On the one hand, it'd be cool to have more mounts designed around the various classes/jobs.

On the other hand, part of the reason for Tanks getting their own mounts is to entice people to actually play the role to help with the underpopulation within the DF, hence why these mounts are locked behind doing a bunch of DF content as opposed to CNJ (Not WHM) where it was a simple quest where you go heal a unicorn and that's it done.

So, while personally, I'd love to see more mounts designed around the various jobs themes, I don't see it happening unless they also implement a new way to entice players to play Tanks in the DF to make up for the devaluing of the Tank mounts that these additions would cause.