All a port means is that the general key previous content will be there, characters included(well, should all be there, depends how they were licensed). It does not mean the lack of new content. More stuff would obviously be added to promote some various things.
Also, to be fair, a lot think Wolf would come back in a port, and that makes it easy to give him an updated design fitting SFZ. Beyond that, Link probably wouldn't get too much BOTW stuff either way, as an extreme redesign is too offputting. It'd likely be just giving him bits and pieces, even less than what he got between Melee and Brawl, which gave him the TP version in pretty much every possible way(which was not really any different from Young Link being updated to Toon Link).
I honestly doubt we'd get zero content from that other stuff even with a port. The thing is, the biggest and more important part of a port isn't the random stuff like trophies, which can be changed out here and there, it's the characters and stages(and items more or less). Music kind of varies. A lot of this stuff would still be noted.
And even if it wasn't, getting a regular sequel is still beyond likely to happen down the line. Another thing to keep in mind is Sakurai might not even be directing the next Smash(might be for a port, but an all new game is another story), so a lot of philosophies could change a bit. So anything we already had official rules for when it comes to character selection could change. Even fanrules could become reality for all we know. That's kind of how odd this situation is(as much a I hate to repeat this, Iwata's death affected a lot more than Nintendo itself and us. He's the reason Sakurai has consistently been asked to be Smash's director. Without him, it's not a clear-cut easy decision anymore. There's a lot to take into account, and while I do think Sakurai has a good chance to stay the director for a bit, he also has things like hand and health issues that makes it a good idea to have him as a lesser(but still important) role to the series, which is understandable for the reasons above. First, his health. You want somebody else who can make sure he won't overtax himself there. Another is that Nintendo can allow the series to evolve by letting new directors try different things. This isn't a bad thing. This could go bad, obviously, but it could go good too. Who knows).
That said, the longer we wait, the less likely a port is. I'd say this is the last year it has a remote chance of being revealed, and it would be a less notable reveal than an all new game, so it might be as early as the first Direct of the year(which may be this month). Likewise, if somehow we do get a port announcement, it's probably the only Smash game that has a remote chance of being released this year.