If a Smash 4 port doesn't come this year as a way to push Nintendo's paid online service than it is never coming. I also heavily doubt they won't announce it around E3 if it exists. Smash Bros is the perfect game other than Splatoon to push online. (1st party wise)
Also Smash bros will have like a year+ from reveal to release. It's not Smash Bros without the hype cycle to be honest. At least for me I won't be surprised if Nintendo thinks the same way.