Triple Deluxe and onward call him Bandanna Waddle Dee.
And Rainbow Curse reverted back to just Waddle Dee.
If we are taking his Japan popularity into account, then we should compare him to other top contenders. According to Push, veterans seem to dominate the polls...yet K Rool appears to have more support than even the veterans, something Waddle Dee doesn't.
The thing that bugs me with Waddle Dee, in my opinion, people only want him so they can "complete" other characters. Waddle Dee was the P4 option in RtDL and suddenly people want him to fill this role. We've seen other characters become popular to complete other characters, such as Waluigi for the sake of "4 Plumbers" or Sceptile for "starter trio." Hell, some want Chrom still so they can complete the "Awakening trio".
Compared to the DK franchise for example some people want Dixie and K Rool for the sake of adding more DK reps. While I do feel the series is underrepped personally, Dixie had a staring role in a game and K Rool was consistently the series lead antagonist for a great deal of time. Even further, popular characters like Isaac, Rayman, Simon Belmont, Inklings all had staring roles in their series. Waddle Dee has not, and only recently got a push from player 4 role to player 2.