I don't know the fandom well, but if I am representative of the ''average fan'', here is how things went for me.
During the ballot, I came to the conclusion that I really wanted three new characters in Smash: Skull Kid, Banjo & Kazooie, and King K. Rool.
I could only vote for one, so I dismissed K. Rool first: I wanted him because his absence felt really odd, not because I'm a fan. I loved the first DK Country, but I could not play the sequels, and DK64 was a huge disappointment to say the least (one of the few N64 games I never finished actually).
Banjo & Kazooie I loved much more, but I thought they were ''unrealistic''.
So, as a Zelda fan, loving Majora's Mask in particular, I ended up voting for Skull Kid, that I wanted since pre-Melee.
With the K. Rool reveal trailer, Dixie automatically became my new number three. And she has merit, because I've never played any of her games! I just know her by reputation, as the third Kong of the trio.
And now, she's my number two.
Pretty sure I'm not an exception. Dixie is an important Nintendo character, but some others where boxing in the same league and were seen by many as more urgent or important. Who's left now? Cranky and Funky in the DK serie, and yes, there is still Conker. But I bet most people who grew up with Rare games will think of Dixie first.