Toned down aether would be fun (having all your equipment scattered around the mud or the whole inventory melted is a bit too much). I did not quite like the crits that caused total destruction of your corpse/inventory, without giving any chance to get it back. I suppose sending to hell could be substituted with sending to warp (so that your corpse/gear is retrievable, albeit with some effort). Sending to another dimension could be changed similarly.

Time crits could be fun with recipient (or its particular body part) going back and forth in time from newborn to the old-aged person with appropriate hp/mp/stat adjustment along the way (not necessarily bad btw, if you end up in mid 20ies you should get a boost I'd say).

I am not sure how popular limb severer will be in today's world - you can forget about combat xp with it.