I majorly disagree.
Rare's post-DKC1 characters are terrible. The only exception and it's an answer for this thread is Dixie Kong. Her design is alright but her implementation supposedly being a character for beginners in Donkey Kong Country 2 was very well executed on top of her unique abilities as Diddy's partner, in contrast to how useless DK is in DKC1. But even then whether you're a beginner or a veteran that actually only factors in your preferences, there are many situations where Dixie is better than Diddy and the opposite holds true, so often you'll find yourself switching back and forth between them and for a good reason. I thought Dixie looked stupid as all hell and being a huge DK fan I didn't like how she "replaced" him (I did not care about how much better Diddy was in DKC1, Rare could have fixed him up), but playing DKC2 I found an appreciation for her because the developers actually knew how to make her likable via solid game design. I did not feel this way with DK64, which was poorly thought out in terms of its cast. Found an item for a specific character but you're not said character? Too bad, do the level all over again. Not to mention Chunky and Tiny are literally Kiddie and Dixie, why not use those two instead? Lanky was an exception, but...he was so awfully gimmicky. In fact none of the game's character controlled well and they didn't complement each other at all, compared to the Diddy/Dixie tag team in DKC2. As a matter of fact I'd go as far as saying that DK64 would have been much better without multiple characters.
It just shows how compact and polished DKC2 is compared to the broken incoherent mess that is DK64, it goes beyond their implementation of characters.