it is an enhanced port.A port implies its heavily based on one game only. They never had this many fighters in the same game, so its not a direct from anything. Its got loads more content and a few new interesting features. I wouldn't call it a port. I think its just Smash never changes much between each release.
2 new fighters vs 64 ports from previously launched games. pointing out things like "the wii fit trainer has a new facial expression" in no way qualifies to me as new. TLoU got new textures when it was ported to ps4,.. it's still a port even though some work was done to polish the port. the reason everyone is saying the smash part was boring is because nintendo harped on every minute change to try and convince you they actually worked hard on this port. but..
..this was developed fast and cheaply. port.
But eh, its not too much more than a port so there's not really much point debating over it.