I think that a wall jump wouldn't be out of place for some characters, but I would definitely suggest limiting it to only one or two wall jumps before before they player has to hit the ground again. It jsut seems to me that DKC could play as a pretty fast paced game, and given they're monkeys and gorillas, a wall jump seems like the kind of thing they would be able to do.
I only played all the way through DKC1. I think I rented DKC3 once and played some if it, but I don't remember it well, so if this is already a thing in the later games, I apologise.
If I were you, I'd also try to improve the "swinging from stuff" mechanic of the game. To me, climbing on and swinging from ropes in DKC always felt slow and a bit unrealistic because the roles were always so rigid. I'd really like to see looser movement of ropes, and the ability to jump from one to another much more quickly. Maybe even include a few different ways of handling ropes, such as holding onto one rope in each hand, dropping straight down from a rope rather than jumping off it, holding onto the rope with feet or a tail to hang upside-down perhaps. I think there's a lot that can be done with swinging... maybe even to the point where most of the game is played in the treetops, rather than on platforms or on the ground.
