Yeah! I've been thinking the same thing. If I make a hack I'd love to have that as a feature. Like there would be units where their "base class" would be the mounted version and they could dismount, and foot units that could take mounts (or wyverns/pegasuses). There would be a sort of "penalty" for the additional movement, or an incentive to dismount.
However, I don't agree that physical units/magical units should be able to swap. Units should either stay one or the other, or be a class that has both (like in awakening)
