Smash Mods

Full Moveset Change

Jab: Allow Attack12 to be interrupted on contact.
D-Tilt: Low BKB, no KBG, interrupts earlier.
U-Tilt: Less BKB, more KBG.
F-Tilt: More BKB.

Nair: More damage, less BKB
Fair: Less BKB, More KBG
Bair: Less BKB, More KBG
Uair: Less KBG
Dair: More KBG

Side Smash: Increase KBG.
Down Smash: Increase KBG, allow some movement while on the ground.
Up Smash: Increase hitbox size.

Neutral B: Always has momentum as if it was a full charged shot. Allow interrupt earlier as soon as momentum starts. Pressing shield while charging gun on the ground makes him drop a peanut (not healing/food, to throw).
Side B kick: Trajectory at 13B, allow jump on contact.
Side B jump: Stronger hitbox.
Side B attack after grab: Allow interrupt from beginning. Allow Up-B out of it.
Down-B: Airpluck speed on ground. Limit to 3 bananas, but they can be plucked anytime.
Up-B: Honestly, I would nerf this. Take away the interrupt but make the explosions bigger when they hit the ground.

Peanuts should be transcendent.
Bananas should slightly spike.

The way I imagine Diddy's final design, he can still be gimped easily but has a good combo game and the ability to stop recoveries.

Whats is BKB , KBG ??

I agree with your suggestion on peanuts , but bananas spike?! Looks no sense a banana spike !

BKB is the base knockback. KBG is knockback growth (how damage affects damage).

The idea of banana spiking (not a strong spike) is to either hurt recoveries more or to help control the opponent on the ground. With Diddy's combos, he normally knocks them out of reach. Imagine the following combo against DK from 0%.

Utilt x2 -> Reverse Banana pluck (pulls them down) -> nair, dair (spike onto banana).

Something like that. The goal is to help continue the combo.