I don't understand what other abilities you'd use on the Hunter instead of just playing an Archer?
There're a lot of really, really good Hunter build options. I'm particularly fond of Stealth, as he can get it up almost instantly from Leaping Shot and it's something the Archer would kill to have. Toxic Cloud is another very, very strong option--one of the few real ways to get poison kills on Perilous. Given that Elemental Mines are often considered one of his weaker routes, I think the fault may lie with your understanding.
How about the people who give keepers crap for not running barrier. I bet every person on this forum has beaten a match without barrier. It is an option, it's not mandatory. And if thats not the case why not hold the elementalist to the same standard of being the barrier ******.
Tbf, a near majority of the Keeper's passives involve Barrier use and her other actives aren't nearly as outstanding as the Elementalist's. Elementalist can afford to give up Stonefist or Immolate if he feels like it, his active selection is just that good, and he doesn't exactly lose out on passives. What else are you taking on your Keeper that's edging out Barrier? Veilstrike? Barrage? You can do it if you want, I guess, but it is bad in a way that it isn't for Elementalist.