To hate the way Diddy plays and want less characters like him to fight against, because he's so annoyingly good, is kind of a funny way to not want Dixie in the game... heh. It'd be like me saying I don't want a Jeanne Echo of Bayonetta because I can't stand playing against her and wouldn't want another character like her in the game because of it.
Dixie Kong though, guys, Dixie, in my honest opinion, is way better than Diddy Kong. And my opinion of Diddy has no bearing on why I want Dixie in this game, really, I just think she's the better character in the DKC series, in nearly every way.
I'm cool with an Echo, it'll do her justice. As long as they change a few poses, a few animations (her jump and duck need to reflect her games rather than reflect Diddy's), give her a new Up Special, and some cosmetic changes like the pirouette for her dash and the gumball popgun for her standard B (with a slight functional difference, with it not dropping nuts to pick up and eat, but maybe instead, the gumballs could bounce? Like Yoshi's new egg throw?). THEN, if they make those changes, then it would do her justice, heh...
What I would like better, but perhaps still realistic. Is some hybrid between DK and Diddy, where Dixie takes a few moves from DK. The Up Special, spinning kong (helicopter ponytail twirl which is what DK's spinning Kong originates from anyway), the side special, headbutt (slams her ponytail down forward, burying opponents), the down special, handslap (slamming her hair back and forth on the ground, exactly what she does in DKCTF), and the grab and throw (where she picks up and can carry opponents with her ponytail). Then the rest could be plucked from Diddy, and then, to me, she'd be the perfect Dixie. And the whole time, she'd still be an Echo, just pulling from DK as well Diddy.