I think this would do better as a compatibility option. Having the player stay at the current height as the floor drops out from underneath is IMO a great effect that can be used very effectively by modders.But it is the way Hexen behaves, and I think it makes more sense. But since you complained about it so vociferously, I've changed it back for Doom and Heretic so that things standing on the floor will stay glued to it no matter how fast it drops, if only so that that spot in E4M7 will work.
EDIT:
Or maybe a DEHACKED flag: NOFLOORSTICK