Good action movie, but the only memorable things are the assassin's guild with their own gold coin currency and rules, and a welcome appearance from a saloon keeper of old in a new modern position that just seems right.
Production and cinematography are good, making it easy to watch. Fight choreography is mostly believable and entertaining (if you're into that sort of thing, and I am). The story and dialogue are mostly good, and there's nothing cringe-worthy.
Why didn't John Wick shoot Iosef (gangster's son) when he had him in his sights in the Red Circle, not even a third of the way through the movie? I know its because the movie is only 1/3 over, but they could have tied it in more to Wick being a bit rusty, rather than some strange hesitation.
Why didn't Wick kill Viggo (gangster boss) when he had the chance? John had to know by now he was in a total war situation, especially since he started it, and was willing to sacrifice anything (his retirement, his life) for it. Letting Viggo go just seems like dumb choice for someone who should know his trade as well as Wick.
Another small annoyance is John Wick is so thorough in taking people out (shown with constant double taps), which I like, but when he chokes out Kirill (Viggo's top guard) in a few seconds, John gets up and walks away. I'm not knowledgeable in such matters, but it doesn't seem like a guaranteed enough time to kill someone, but maybe only enough to knock them out. Once you gain control of the situation, why not take a moment to make sure, especially when its one of your (few) defining characteristics?
What else.... how about the biggest one of all. If you're going to run a criminal enterprise, make sure all your people, especially family, know all about the assassin's guild and who's in it.