Oh boy, Krystal.
Krystal ~ 35%
Krystal is one as one of the most obnoxious fan base in Smash speculation history and it's pretty obvious why especially since her Smash Boards's club was called yes, the **** Staff (not kidding, go look up the Brawl Character discussion). In a way, I'm glad that I wasn't around for pre-Brawl or I would have ended up hating her. But now that Wolf is in and that there's no one else that would get considered for a spot, this is Krystal's first real shot into the game and potentially her only one.
Krystal's advantage is her Western popularity. She was extremely popular during pre-Brawl (around the same level as Wolf's) and she's still a very popular request in the West to this day, topping the Top 10 as of now (it's just her fans are for the most part, silent, contrary to pre-Brawl and what most people think of her and Smash now). Even if a lot of the requests is based around being a female, it's still popularity and since the fans do want Krystal and she has been requested for such a long time, it does help her case.
Sakurai also seems to note her abilities as a fighter. Sakurai did note that Krystal was valuable in combat in her Brawl trophy description, so it's not like she wasn't capable of fighting. Another thing to note is that pre-Brawl, Sakurai hadn't even heard of Krystal and while this doesn't definitely guarantee her inclusion, her combat ability being noted and the Smash Taunt in the Lylat stage indicates that Sakurai might be looking at her for this game.
However, this is where her positive ends. She runs into several major issues that makes it doubtful for her to appear. First thing is that Krystal is a mixed received character. Krystal is a very polarizing character, considered (if unfairly) to contribute to the downfall of the Star Fox franchise and many fans loathe her as a character, especially in Adventures. It doesn't help that Krystal was always outdone by Wolf in requests in Japan by a far margin and has never been all that popular of a choice. Krystal is going to have to hope that Sakurai places a large emphasis on Western demand (although Little Mac's inevitable status is an indication that Sakurai is focusing more on the West). If so, then she does have a fair shot but if not, she is going to get overlooked.
And she is not replacing Falco or Wolf. If she gets in, she will have to get in as the fourth Star Fox character, which isn't likely.
Want ~ 50%
Don't care if she gets in or not. If she does, great. If not, then I won't blink an eye. Although I will say in her defense that there are worse fan base for Smash 4's speculation scene than Krystal and the staff does look very interesting.
x5 Mii
Predicting that Little Mac gets a 81.43%.