+1, I agree.

It wasn't until a few weeks ago that I've noticed again that it was actually Heavy debuff, and not the mount being Lamed debuff (which I think was 1.0).
When I've noticed that (while on whm), I've just dismounted and Esuna the Heavy debuff off myself, and sprinted away on my merry way.

It's nothing more than an annoyance now, rather than me fearing that I will be wrecked when my mount gets lamed heavy and tosses me off onto the floor.
Wait... do they even auto-dismount anymore if you take too much damage?... Yeah, it's been that long that I don't even remember.