If it's still possible Heavy, could you add an "other" option. Knowing of the creativity of some players, I assume people will just start putting hidden alt players on foot everywhere with nothing but a bola or two on them.
I think if bolas were completely removed, dump and run tactics and offscreening dexers would be a problematic issue in the future. Just my opinion though.
I definitely think that adding a delay to the time before a pet can start the casting process after dismount would be useful, and if it's true that nightmares became insta-cast by mistake it was a big issue that the staff should have been very quick to fix. That way you have a decent opportunity to disrupt the pet if desired. More of a fix to nightmares (and other casting mounts). Between that and starting to ride a real mount or faction warhorse, I think you'd experience a lot more reasonable results.