I would go with John Wick. it is a great revenge movie. He loved his dog and made sure those that harmed the dog paid the price for that act. John is a simple man and makes it very easy for Keanu to play him. All of Keanu's other roles could have been better if Keanu had more range. Neo, Johnny Utah, and even Ted had more complicated lives than John Wick.
John Wick 2 has me torn. part of me wanted it to be parallel to the first in that someone stole his car and revenge ensues. the other part liked that they tried to interject a mythology behind behind who John was. I don't know if they succeeded, but the mythology part did introduce Ian McShane's character so that one does get points. but that story breaks down at the end because the writer really wants to do John Wick 3 so he wrote a very implausible climax.