Rule Changes That Affect Your Plot (or, 3.5 and the Simulacrum War)

[Plane Sailing]

Have you ever had a plot that depended heavily on some aspect of the rules- perhaps even just a quirk of the rules- and had those rules change (i.e. a new edition comes out and you're still playing that campaign) to make said plot impossible?

3.5 took away the Mind Flayers astral projection ability, which was fundamental to my whole main campaign arc. So I just didn't bother with it. all my mindflayers continued to have astral projection, and will for all time to come (it is just too useful to have recurring villains who aren't really there, but are just manifested astrally projected bodies... their real bodies lie safe on a plane far away and if you want to stop them, you've got to get there...)

Cheers