Every time this gets brought up I keep saying the same thing.
It's only been 3 years since the last Metroid game. And even if you didn't like Other M, it's only been 8 years since Metroid Prime 3. Compare that to the gap between DKC3 and DKCR, which was 14 years. 11 years if you want to count DK64.
DKC deserves a new trilogy at this point. And lets not forget that Retro has a 2nd team now and they probably are working on something else. DKCR definitely had some room for improvement, so I hope Tropical Freeze is the equivalent of DKC2 to DKC1.