I’m not sure what the whole show-bang with “final characters won’t be hype” is about. Cloud was quite late in Smash 4’s DLC run as well (only succeeded by ballot winner Bayo and recency-based pick Corrin. Even if two DLC cycles a pattern makes, I don’t see how we can’t end with someone hype. Statistically, it‘s likely we won’t get two frontrunners (because of the known and discussed problem of there only being like five frontrunners out of the bazillions of characters) but this almost pompous anticipation for a lame first party is off-putttng (though of course, hype responsibly)
I guess it's because a lot of the games/DLC have ended on a relatively "low" note.
Not sure who the N64 game's last reveal was - I'd guess Ness, since I believe he's toughest to unlock, but I don't think the original site acted like a blog (unless the Japanese site was different).
The last Melee reveal was, from what I recall, Mr. Game & Watch (he's the last character that you unlock), which was probably an example of a character where people would literally respond to with "who?" (I know that the Game & Watch galleries on the Game Boy were a thing, but I don't think people would expect an amalgamation of 20+ unrelated Game & Watch games to be the final character)
Brawl's reveals ended with either Wolf or ROB. I think the last few characters wound up getting leaked, and they were met with disbelief, to say the least.
The last base game reveal for Smash 4 was the dog from Duck Hunt, or Dark Pit considering that he didn't get his own trailer and we didn't even know that he was playable until the 3DS version came out. The last Smash 4 DLC reveal was Bayonetta, though the Smash Ballot muddies that up a bit. (the last one fully picked by Nintendo/the developers was Corrin)
Then for Smash Ultimate, the base game ended off with Ken and Incineroar, while the first season pass ended off with Byleth.
All of these characters have their fans, to be sure, and plenty of people wanted to see them (I voted for Bayonetta in the Smash Ballot, and I think that when the concept of echo fighters was announced, a lot of people expected that we'd get Ken), but compared to the likes of Bowser, Sonic, Mega Man, Cloud, Ridley/K. Rool, and Banjo (among others), they weren't the highest points of their respective groups. (Bayonetta was extremely exciting for me, but I can see how people not familiar with the franchise might view her as a disappointing pick after Cloud and Ryu - I can't recall what kind of reaction she got for her inclusion, since most of the complaints that I recall were about her gameplay)