Knuckles has been an important Sonic character since 1994, and his first appearance showed us he isn't someone to be messed with (by punching the super out of Super Sonic which nobody has done since), last playable appearance (at least in 3d modern games) has been in 2006, he hasn't been playable for 12 years
He is an echidna who guards a giant emerald called the master emerald, and he has been a respected member of the Sonic franchise since 1994, and he was one of Sonic's first rivals, but in recent years they made him a complete idiot, which is wrong since the first time Sonic met Knuckles, knuckles set traps that both Sonic and Tails fell into, he was a great character who was ruined
But in smash brothers, he fits the qualifications perfectly
He is a cartoony character with giant, powerful fists, he originated from a highly popular video game, and he has been on Nintendo consoles before.
His style and place as a powerful fighter fits in smash better then characters like Tails or Shadow, two other highly requested sonic characters. In conclusion, Knuckles would be perfect for smash because of his extensive past with sonic, his fighting styles and abilities, and his overall uniqueness within the video game universe as a whole.
Here is what his moveset could potentially look like:
He is one of my personal and many other's favorite sonic character, and he doesn't not deserve to be a simple assist trophy, he should be duking it out with Mario, Donkey Kong, Link, Bowser, Pikachu, Sonic, Snake, Megaman, Pac-Man, Ryu, and many more
In conclusion, Knuckles would be perfect for smash because of his extensive past with sonic, his fighting styles and abilities, and his overall uniqueness within the video game universe as a whole.
So please sign and hope someday Knuckles can join the super smash bros roster