Well, to be fair, I think the lack of new characters is why people are viewing this as more a port and less of a new game which is silly but it does take away from the Smash hype cycle. Melee, Brawl, and 4 kept increasing the roster each time even though there were some subtractions on the way. Only seeing a couple new characters might feel disappointing at first but then you've got to remember they are already at 65 and not every single character is ever going to make it to this game. Your fanboy/girl wishlist will probably never come true for your obscure favorite characters.
What new characters are you expecting or that they can possible still add? Realistically, I think an ARMS character has the potential to show up. I think King K. Rool and Dixie Kong have a potential shot. Same goes for Chibi-Robo. Considering that all third party characters are in this game and Nintendo is giving each company just one character to represent, I'm actually starting to believe that Rare/MS may get Banjo-Kazooie in this game. Or Nintendo could do something to strengthen their growing Bethesda partnership and have someone like the Doom Marine appear. What else is there in third parties? (So sick of the Goku requests. Goku is not a video game character.) For Nintendo, what other character needs representation at this point? Perhaps Paper Mario makes it in. We've got three Links so why not three Marios. A second Xenoblade character?
Melee to Brawl was around 7 years. Pretty much all of the GameCube and the beginning of the Wii unfolded in that time for new things to be added and base the game around. Brawl to 4 was about 8 years. This is just 4 years. There hasn't been that much that was missing in 4 from then to now. Yeah, some franchises have a plethora of viable characters compared to others but how many entries from a franchise need to be included in this game? Look at how fans complained every time an entry was cut or subtracted between editions. If the expectation is that "once in - always in" it makes it harder to add new characters from a franchise.
Maybe it is Smash Bros. Greatest Hits edition but it's like a Smash Bros. Virtual Console. I can have all those characters and stages in one game without having to go back to previous editions and switch consoles to play them.