I never understood why people want characters to leave in the first place. I don't like Lucario in the slightest, but I'd rather have him stay, as his fans would be let down if he left.
Speaking of which, I find it heavily ironic that you're not upset over the possible disappearance of Lucario.
If any characters 'sides Snake 'n Sonic leave; they are 3rd party characters, after all; Sakurai clearly learned little from the outrage of people complainin' 'bout Melee characters leavin'. If Lucario leaves, clearly it's bein' replaced rather than outcasted like ICs... but at this point, Sakurai knows not t' make clones. Why disappoint the Lucario fans by introducin' a character that's guaranteed t' not be a clone? Unless Sakurai is adamant on every series not havin' more than four characters, I can't see the logic behind it.
... And either way, I'll be sadface.
I don't care about any of those guys leaving. Not important besides the third party ones, which is fine. Ice climbers were fun and unique though.