I've been a big fan of the Dillon's Rolling Western series since I played the original, and while I do find his inclusion in Ultimate unlikely given the limited number of newcomers we're gonna get, I'm still gonna support Dillon!
This is going to be a major stretch, but with the introduction of Echo Fighters, how would you feel if Dillon became one based on Sonic?
The two were already compared before, and while Dillon does have differences in guns, ground slams etc, and he doesn't really do homing attacks, he could still share a similar "skeleton" as Sonic (body proportion-wise... though Sonic is kinda lanky tbh), and Sonic does use punches and kicks as well as basic rolling attacks, which could also translate to Dillon. I guess only the up + B and Final Smash wouldn't really fit and would need to be changed + some other minor tweaks here and there.
The best outcome for Dillon would be a unique moveset of course, and I think Echo's might have to be under the same series/franchise anyway, but just food for thought.
Naw. Dillon being an Echo of Sonic just wouldn't work. I wouldn't mind it too much if it were actually feasible, but looking at Sonic's moveset, it really isn't. Dillon's legs aren't nearly as long proportional to his body the way Sonic's are, and Sonic uses his legs extensively in Smash, like in his Up Air, Down Air, Down Smash, etc. These moves couldn't work on Dillon unless they made his legs longer, which would be incredibly jarring. The only moves I can see translating decently from Sonic to Dillon are Sonic's Up Smash, Neutral Air, Down Throw.... and that's kind of it. Not even Sonic's Spin Dash would work well as Dillon's Charge Roll, as Dillon uses his roll as a ramming attack, so having it go through enemies the way the Spin Dash does wouldn't feel right. In any case, Dillon's proportions just wouldn't work for Sonic. Just look at their models:
Not only are Dillon's arms much longer compared to his legs, but his entire torso is much longer and wider than Sonic's. Sonic's legs are around the same length as his arms, if not a bit longer, and their noodle-like quality actually does come into play with his moveset, like in his Up Air where he uses them like a pincer, or his Down Smash where he does the splits.
Keep in mind that Echo characters aren't semiclones on the level of Falco, Lucas, or Toon Link. If Dillon were to be an Echo character of Sonic, his skeleton couldn't be "similar," it would have to be identical. Just look at Dark Pit and Lucina. They're almost one-to-one with Pit and Marth, with their animations and attacks. You couldn't do the same with Dillon and Sonic, as doing so would require stretching his limbs in an unnatural way. Not to mention the fact that Sonic has very agile animations to reflect his great speed. Dillon can roll fast sure, but anyone who's played his games know that he's not a very fast runner, and his shell would also keep him from twisting his body the way Sonic does for his movements.
While Sakurai does take liberties with characters occasionally, he still aims to have them be a proper representation of their character in their home series. That's why he was so hesitant on Ridley for the longest time, and when he implemented him in the game he made sure to capture his cruel and brutal nature to make for a good representation of his character. Making Dillon an Echo character would be a huge
disservice to his character, as not being able to do any of his basic moves such as a ramming roll and especially not being able to do claw attacks means that you just wouldn't be playing as Dillon. Not to mention how none of Sonic's specials work well for Dillon, other than Sonic's Side Special being charged up in a fashion that could work for Dillon.
I apologize for this incredibly long winded and rambly post, but the "Dillon would/could be a Sonic clone" argument is one that I very much resent, especially since it comes up almost every time Dillon being put in Smash is brought up. I guess I just wanted to dump all my thoughts on it in one go. Sorry 'bout that. If I made an error anywhere in this rant, do let me know, cuz I feel a little lightheaded right now, and I wouldn't be surprised if I overlooked or screwed up on something, haha.