Enigma is the best armor for a lot of classes even without the teleport. Even sorcs use it. The combination of high defense that does not rely on the base armor’s stats, very high magic find, %damage reduction, strength increase that allows you to put more points into vit instead of str, Increased life%, high life after kill… It’s just straight up better than most other armors for casters and even some melee
Spirit shield is cheap yeah, but you can’t get one until you find a 4 socket monarch so mid hell difficulty without trading for it. Spirit sword is alright early on but HotO and occulus are better by a good margin. I don’t really consider spirit that op.
Insight is great early on for sorcs, but it’s just convenience. It’s not op at all. Infinity is better for end game. Treachery is pretty good, I’d say there are better options for a merc out there though.