Do the bosses have randomized mechanics in WoW? I'm curious what you mean by anything can happen because I've never played it before. I think it'd be fun and would have players look at the enemy cast bar more which is useful in a lot of fights without AoE telegraphs

I do like a lot of the old ARR dungeons, since quite a lot of them had unique mechanics or other things to watch out for other than the boss

The first example I can think of is Aurum Vale and the mechanic to eat fruit to get rid of debuffs. It's especially handy if anyone gets hit by bad breath during the last boss
Playing more with the environment would be fun