That isn't exactly true -- many DKC levels had multiple hidden barrel routes that would bypass lengthy platforming sections. They're essentially little more than shortcuts, though.
Anyway, I've always thought the problem isn't so much with the path, but rather that all of the levels are just very repetitive and simplistic obstacle courses. The challenge is nil, there's hardly any variance between levels beyond the type of level (outside, cave, underwater, mine) and the meaningless backdrop, and the animal companions are just there for the fuck of it and don't really shake up the gameplay whatsoever.
