Nathan Rabin said it best in his post over at The Dissolve:
I’ve got to admit: This trailer got me all kinds of excited. I’m a sucker for movies involving adorable animals, dogs in particular, and I think the hook of a man of violence unleashing a bloodbath in revenge for the slaughter of his beloved animal companion is pretty brilliant. And while I generally abhor violence, no amount of bloodshed can atone for the loss of Wick’s dog (who looks like a Scruffers to me).
Many thanks to The Dissolve for the screen capture