Followers -- what am I missing?

[MongoJerry]

You only get 1/5th of the MF%, GF%, and +experience to kill that you put on the follower, so it's not really worth going out of your way to stack those stats on them. Meanwhile, the follower gets 2.5 times as much benefit from any straight stats -- str, dex, int, vit -- so it is beneficial to stack those on the followers. For the templar, vit is crucial to allow him to be a partial meat shield. The enchantress and scoundrel can deal a decent amount of supplemental damage if you stack int or dex, respectively, on them.

The auras are good, but most importantly, the cc's they provide are the greatest benefit they provide.