I don't think Arnold's acting improved any over his hiatus but, the director is Jee-Woon Kim, who made The Good, the Bad & The Weird, which was on the more entertaining films of the last decade.
It is pretty much Arnold's western, which he hasn't really done before. I hope he does get back to making some more high-concept action flicks in the near future though (stuff like Predator, Terminator, Total Recall). Although it does make sense to do something more straight up actiony like this and Expendables for his return to movies.
I wish Arnold wouldnt play retiree and hes unable to hold that minigun himself, its a bit sad, they shouldnt do it like that and that comedian should be killed off in first minute of the film.