I don't know how anybody can look back at Smash 4's newcomers and try to call it underwhelming.
Ok, I'll play Devil's Advocate here.
"I don't know how anybody can look back at Smash 4's newcomers and try to call it underwhelming" is absolutely an opinion. In much the same way that there may exist people around here who don't think that K.Rool and Rildey are not the hypest thing in the world now.
You've got Villager, the face of Animal Crossing, the last of Nintendo's major franchises to not make it into Smash.
...which not everybody may like. Think about the inklings - yeah they had fans, but a lot of people more
expected them in smash than
wanted them. Just because something expected happens doesn't mean that everyone will think it's the best thing in the world.
The super fighting robot Mega Man, one of the most beloved video game franchises ever, back in his purest form.
...which doesn't really hold nostalgia value to anyone who hasn't played Mega Man. Or to the people who are Nintendo purists.
Little Mac, the star of the Nintendo franchise most suited towards fighting and a fan favorite.
...again, not every fan was big on Punch-out. It's pretty niche, old, and region-specific.
Mii Fighters on the whole were tremendous, it allowed for so much creativity and fun.
...but the customization was a mess and there was no easy way to unlock all of the hats/outfits. Plus a lot of their moves were expies of other characters.
Pac-Man, the grandfather of gaming and the king of the arcades.
...again, Nintendo purists prefer fewer third parties, and he came with what is widely considered the ugliest stage.
Fire Emblem got a character without a Down-B counter (okay this a meme but Robin is at least by far the most unique FE character).
...if that's the only thing that people hate about Fire Emblem... Not to mention he's an avatar with little actual personality and got in above the main character - who was also done very dirty in exchange.
Shulk was a huge fan desire and brought Xenoblade back into popularity, pushing it to be a real franchise.
...and gave another generic anime looking guy from a very niche franchise, enough that many people considered him a 'Literally Who.' Also region-specific enough to be revealed in a Japan-only direct.
Wii Fit Trainer was the meme, her being initially (and somewhat post-release) unpopular is typical.
...and some people prefer time not be spent on weird WTF characters.
Duck Hunt was the B-Side to Super Mario Bros. and one of the most well-known (and infamous) NES games.
...and is one of the most hated characters in gaming. Also, well forgotten by a lot of the fanbase as well.
And Rosalina, Greninja, Palutena, and Bowser Jr. were also characters who were extremely appreciated by their fandoms.
...Rosalina was pretty well a character that Mario was shoving into everything by that point, so again the difference between
expected and
wanted. Greninja was widely considered the character that took Mewtwo's spot and was hated for it, also that X/Y were very recent so it didn't have much time to gain traction. Palutena was another expected character, but was also destroyed by the customs, both before (why is she so special?) and after (why is she so bad?). BJ was from an older game at this point, and contributed to Mario oversaturation.
And the clones of course were all from oversaturated franchises, while Alph stayed an alt costume.
I I'll even ignore the immense weight of Ryu and Cloud joining as DLC.
Three veterans who cost as much as newcomers, instead of highly requested characters, including one who further oversaturated Fire Emblem.
Three third parties, two of whom are from rather large series, but started to mark the shift to the 'too many third parties' argument. The third being one from a relatively niche game series which is more than a little inappropriate, and declared the winner of the ballot, when it's now seen that that data was fudged.
And a complete newcomer from an entirely overrepped series from a game which hadn't even released in all regions, making him blatant advertising.
Meanwhile, there were several clear frontrunners in the 'fan requests,' who all ended up not in.
Not every fighter strikes gold, but you can't deny that the game brought some heavy hitters as well as some highly-desired fan choices. And don't act like every Smash before For had a golden, flawless roster. 64 had freaking Jigglypuff, and Melee brought in the likes of Dr. Mario, Roy, and Pichu. As much as people hated Brawl's roster before release, in hindsight, it has the fewest 'questionable' picks. You can forgive Smash 4 for having Lucina and Dark Pit.
But it is also wrong to declare that Sm4sh was flawless for
everyone for having things that
you like. Each person will see their own thing, and not everyone likes or wants the same as you.
---
Now, before anyone gets mad and wants to argue, the above aren't necessarily my opinions. I just wanted to play Devil's Advocate for everything. For me, there were some characters I really liked, and some I really didn't. I do consider Sm4sh one of the weaker rosters since it cut many of my favorites while not delivering any newcomers I wanted. Brawl was my favorite before Ultimate simply because that was the roster that gave me my hypest newcomers.
So yes, I found Sm4sh underwhelming. It didn't deliver Ridley, K.Rool, the Pokémon Trainer, it cut transformations, and only gave me a few characters I like and no newcomers from any game I had ever played. I accept that there were probably loads of people who liked it, which is perfectly fine. I didn't, and I stopped playing Sm4sh within about a year. Brawl held my interest significantly longer.