I'm excited for him because I barely remember anything I played on the NES, I remember what games I played but I don't remember my experiences with them as a child, Duck Hunt however along with Excitebike and Marble Madness are games I remember playing as a child because they were the ones I played the most, Duck Hunt a liitle more than the others because my sister and I would always compete for the high score so we both eventually got really good at the game.
So Duck Hunt Dog is a delightful addition to Smash 4 in my opinion, he WILL be one of my mains, I'll practice with him as much as I can to main him because the DHD is a personal character for me.