This isn't like some annoymous 4chan post, Vergeben has leaked so much other stuff outside of Smash that's turned out to be right. Just look at his Reddit activity and look at the stuff surrounding SC6.
https://reddit.com/user/DasVergeben/comments/
He's now saying a League of Legends fighting game is going to get revealed soon.
Vergeben has also had a number of misses in terms of predictions for games and announcements all around. He’s basically throwing all kinds of stuff out there and some of it is correct, but a fair amount isn’t as well.
Remember he also said Simon Belmont was supposed to be revealed at E3 and he wasn’t regarding Smash.
Predicting Ridley is a thing that seems to stick with people because “he wasn’t that likely”. My issue with that is Ridley has shown up in “leaks” for years at this point and was such a highly requested character. He wasn’t a lock for the game, but if a leaker threw him in, and it actually was true, his credibility would increase in the eyes of Smash.
Ice Climbers were the safest bet, most people were expecting Smash 4 to be ported over with additions, so no cuts from that game was all he predicted (People tend to confound other leaks with his, thus validating him when in reality he said nothing else about the others returning). Snake was a little more suspicious due to the whole Konami issue, but he was also highly requested and it wasn’t impossible for him to come back.
His other claims are still completely unfounded. Simon Belmont is nowhere to be seen, as is the Minecraft representation he claimed was in the game. Additionally, since then he’s started to trickle out vague details with no backing (Not knowing if Isabelle is unique, playing coy with we have a Gen 7 Pokemon). That doesn’t really make any sense to me to be doing that. I doubt he has someone leaking information to him like that even if he did previously get legitimate information. It also reeks of arrogance.
I’ve seen the theory he might have only seen the E3 build in action (This has appeared multiple times at this point at events, much easier for it to get out) and if he had any info on Smash, I lean towards that being the only legitimate thing he has seen. All his other claims are unfounded. In addition, Smash Ultimate’s Everyone is Here wasn’t predicted by him truthfully, it’s not like he said Pichu or Young Link were in. He also missed Daisy.
All in all, Vergeben just has too much against him at this point for me to reasonably believe his predictions. Until some content gets shown that fits within his info, I won’t believe any of the more recent stuff. Even more importantly for this thread though, he’s said nothing about King K Rool at all, and has indicated multiple newcomers are still to be revealed. Even if he’s right, that’s still not a death sentence to any particular character.