I am so behind having Dr. Eggman in Smash4! Now the Sonic games aren't my favorite, in fact Sonic in Smash bums me out (No disrespect to Sonic Mains, but I've had my For Glory moments.) EGGMAN THOUGH. Why, he's been such a fascinating character through and through. From his personality to his design. And a mustache that puts Mario, Luigi, and Wario to shame!
I really like the robot design, and can imagine him being a hulking R.O.B. with Bowser Jr.-type specials. But what I'd really like is to see Eggman on his feet. I can't think of the moves he would use without any robot suit, but he would fit right in. Ultimately he would play with a Ganondorf personality: Forcing characters to stay in front of him, and then attacking. Unlike Ganondorf, he might be floaty, despite his weight and size.
Anyways, I'm geeking out at the possibility of Robotnik.