Eggman can just use the Egg Walker from Sonic Adventure 2. It'd be the perfect way to represent him since it's his only playable appearance in a main line Sonic game.
Not to mention the Egg Mobile. It's his most iconic vehicle that's appeared in almost every game in the series.
The thing with the Egg Walker is that when Eggman was using that, he wasn't a Boss Character in that, instead he was a Rival Character to Tails
If they want to Represent Eggman, the Playable character from SA2, then perhaps that could work, but if they want to Represent Eggman the Boss that's in pretty much every Sonic game (Most of them at least), then the Egg Walker would not show that off at all
The Egg Mobile could perhaps work, but it might be a Bit lame and not show off How Crazy Eggman can get. The Egg Mobile is usually the Appetizer that Eggman Displays before he gets to the Real stuff, The Big Stuff.
What I'm trying to say is that Eggman is not Impossible character, but What I will say is that it would be very hard to Represent Eggman as a Boss Character, due to the usual size of his Machines, and Sakurai in that Interview just said he Wants to Represent Boss Characters as Boss Characters. If he sees Eggman as a Boss Character (Which I'm sure he does) than that presents a Problem. You could make Eggman work, but The Sacrifices that would have to be made would be Huge, bigger than Ridley.
One sentence in and seeing the size of the post and somehow I knew this was going to turn into a theory about Shadow.
You gotta let him go, hun.
Also Eggman has already been in a fighting game in his mech, it can work.
So Why exactly do I have to Let Shadow Go?
He's a viable Option, He has alot of Merit to be in this game. I don't mean to sound Frustrated, but Why do I have to Ride on Eggman, or for Base Game, Ride on Shadow as an Echo Fighter to be taken seriously in this Speculation Sphere
Is Shadow not Viable because of the Assist Trophy. I could understand if you think that might present a Problem if perhaps you think the Smash Dev team sees the Assist as enough Representation.
But seeing the Bomberman Costume, that shows they are reconsidering the Assist role for Characters, especially since Bomberman uses the Assist Model asset to make his Mii Costume.
Plus, If Shadow never had an Assist, but Hypothetically we didn't get FP2, there would just be no Shadow Assist Trophy in the game. Shadow would activily be downgraded to just a Spirit, when he's had assist since Brawl.
I understand that Most people here do not see Shadow as an Option, but he still has alot of Merit
-2nd Most Popular Sonic Character in the fandom
-Very Requested Character in Smash fandom
-Has Assets to re-use in the game, including a AT Model, Sonic's Skeleton, for Easier Development
-Has very interesting unqiue Moveset ideas with Chaos Abilities and Sonic's Unused abilities like the Boost, Light Speed Dash, Black Tornado, along with his Rocket Skates
-Head of Sonic team's (Iizuka) Favorite Character
-Sakurai has a thing for More "On Edge" characters
-Relevant to his Franchise
-SA2B was the game that introduced Sonic to the Nintendo Audience
There are legit reasons to have Shadow as a Character to Speculate. Like I said, it's fine if you guys don't think he will get in, And I will admit he has competetion even within his own Franchise, with Eggman, Tails, and Knuckles, who have their own Merits that rival or perhaps even Surpass Shadow, and that's not getting into other Potential characters outside the Sonic Franchise
But you guys do not have to look at me like someone that's delusional. It does kind of suck sometimes you know. I do acknowledge that some of my theories have been off the wall, but I'm person that just likes to speculate, and I think Shadow could be in this Fighter Pass. That's really it