It's the trinkets and little things they drop that are what make rares worthwhile.
Sulik'shor (spelling) drops a really nice little trinket for example. 500 to all stats.
It's actually a clickable item that just replaces a flask. 500 to all stats isn't great considering flasks are +1000 to a main stat.
I'd rather have 500 to all stats vs just one stat.
Not to mention that item doesn't get used up like a flask.