This is a bit hard for me, as certain mechanics I dislike have games that do pull it off well so it really comes down to the designers. For instance, I have never minded the ones already mentioned (well maybe MP death one) as I know games that do them right.

These were the only two I don't care for and even then, I'm not terribly bothered if the game does it.:

Save points that restore health, I just feel like it undermines the use of items.

Randomized treasure chests, because some of my favorite gaming highlights in old school games is obtaining that awesome Axe or piece of armor in the dungeon. Turning it into a grindfest just kills the discovery factor.