Over the years Dedede has been the Most recurring boss in the entire Kirby series. And while his fights make use of his staple attacks, I think some of his better abilities and attacks should be implemented in the next iteration of SSB. Here's some ideas I have.
King's Revenge- Dedede like any other good boss saves his best for last. During battle he should have his normal stats, however once he's received enough damage he gets angry and unleashes his real strength. At 70% he'd start to steam abit and increase his overall speed by 1/3. And again at 140% he'd throw his old hammer aside and take up his axe (as seen in Kirby TD) which increases his swinging range by a foot, and increases his damage% output by 1/3. Making him a dangerous glass cannon fighter.
His tilts, dash, and aerial attacks can remain as is.
However some changes to his smashes, specials, and fs would be to reflect on his fights in SS:U & TD (Masked Dedede), his fight in Kirby's DL2, and his jump attack from Kirby's EY.
>.Smash Dedede jumps up about 3.ft high and forward before bringing his hammer down on his opponent's head. It buries the opponent and deals 19% damage.
v.Smash Replace with his current v.Special but shorten the charge time abit. It deals 26% damage.
N.Special Inhale/Breath Blast- It starts of the same as his normal inhale, but after 2.sec of inhaling, he'll stop with his lungs full, then spit a explosive shot of wind that deals 15% dmg.
^.Special Similar to current, however Dedede keeps his hammer ready, and at the highest point of his jump. Dedede free falls with his hammer out and crashes down on his opponent. His body does the same knockback and damage, but if his hammer connects it'll cause meteor smash in the air and bury opponents who get hit while on the ground. Dmg% unchanged.
v.Special Tornado Swing- After winding up for a powerful swing Dedede deals a swing that sends him spinning rapidly. He can move left and right, and once his hammer connects with a opponent, it deals a single powerful blow that sends opponents flying. It takes 2.5 seconds to fully charge, and leaves Dedede dizzy for a couple seconds after use if over charged. It deals 30% dmg at full strength.
Taranza Tag Team- Taranza appears in the background and throws 6 magic spheres at Dedede who can hit them in the direction you aim with the analog stick. Each sphere deals 4% dmg. Then Taranza pours all his magic into 1 large sphere. When Dedede hits this one, it'll ricochet off of the stage and opponents (it deals 6% dmg per hit and upto 3 hits) before causing a large explosion that deals a extra 14% dmg. (Upto 56% total)
Extra- He should have a taunt where he puts his mask on, much like Lucina's mask taunt.