About Sakurai and greedy fans:
I think Sakurai is quite aware that people will always want more.
Smash is a giant franchise and a symbol/representation of gaming story, it could easily achieve 100 characters before going "too far".
Also, people would pay for it. While Sakurai may want to leave the project, Smash is money.
Sakurai is actually paid for all the hardwork and I doubt his conditions are bad because of Nintendo. I don't think we need to treat as he is doing us a favor.
That said, I think this game was done to silence the Smash fanbase at least, since they picked most of our most wanted newcomers.
About Dixie:
I was already expecting that she would not make into the initial roster. There's no way they would make her a newcomer and show her aside from the K.Rool trailer while they could double the hype over the same video. At the start I thought she'd be a echo fighter showed later, as most people actually thought. It seems to me now that Dixie was a considered newcomer for this game, but K.Rool stoled the spotlight. I'm not trying to start any anger about this, I'm quite happy with K.Rool inclusion, and it's hard to say that she was more important or something like that.
DLC is our final hope. Maybe Sakurai felt two Dk newcomer were too much, and is trying to avoid the Fire Emblem drama.If they add Dixie and, to a extent, Waluigi (while I hate this one, I have to admit he is wanted) as a DLC... most people will be satisfied.
The truth is that with this leak Dixie is the UNIQUE long request character that is missing. Let's try to show that.