Quivo destroys the Diddy wall. F' Toon Link.
And ****s been around for a long time, was obvious within the first week of the games release. You can check the MLG guide thingy I did on Diddy Kong because I mention the setup and that was like summer 08, heck you can see me use it vs Snakeee to 2 stock him at COT4 (not saying I invented it, its one of those obvious things that shouldn't be attributed to anyone).
I use to wall a lot. Now I don't really anymore. I should go back to it but there are just so many other things Diddy can do and I've been having a lot of fun trying different offensive things. The big thing I'm working on now are edge canceled diddy kicks on both the edge of the stage and edge of platforms. You get your jump back because you hit the ground (I like to do it after using both jumps), you have no lag, its great for shield pressure and you can shoot through the opponent safely if they don't get hit. With a banana in hand its extra deadly and it can also push an opponent off the stage who is sitting to close to the edge and lead straight into a spike.
I'm sure I'm not the only one who edge cancels things (I'm also working on edge canceled dairs).