Last time we talked about this, I went back and played a few matches with him and...I actually had a ton of fun. I'm not sure if the high skill floor is ultimately a good idea, and there's definitely improvements to be made to the overall package but I now think the idea is solid.
I mean. The UI would have to change slightly for you to collapse two Echo Fighters to one character, but it's otherwise arbitrary (and may not even exist). Regular clones and semi-clones still serve a similar purpose, but the concept is more broad since it allows you to make more changes, and pick characters that would have to be rigged differently.
That depends on what you wanna do. If you're using Bass's unnamed buster from his original appearance, then he could be pretty easy. If you're using the Bass Buster, then he's harder because he'd have a normal forward tilt, and his neutral attack and neutral aerial would be 8-way directional projectiles. Regardless, he'd need a new Up Special, as Treble's movement option is free flight rather than a bounce pad. He also can't slide, but Charge Kick exists, so you could just give him that.
Proto Man on the other hand, has a generic Rush Coil variant, and doesn't necessarily have to use his shield (he doesn't in Mega Man: The Power Battle/The Power Fighters). If he does though, I assume it would give him Link's/Hero's shield mechanic while in the air (rather than a reflector), and as a balancing agent, he'd take 1.5x damage, and have a slightly less lenient buster.
Roll's appearance as a playable character within the Mega Man series gives her a melee attack, and she has to put on her buster in Marvel Vs. Capcom 2, implying she doesn't have a variable weapons system. She's probably the hardest out of the three unless you just went "eh, just give her an arm canon and call it good".
I'd say all three are options, but each one has their own problems, which is probably why they didn't do it for Super Smash Bros. Ultimate despite it being a pretty obvious move.
Roll actually isn't the same bodyshape as the others. She cannot be an echo. It's clone or higher within this factor.
Uh, no. It's not simply the UI. It literally is saying "they share the same number", period. They have to entirely change the Echo system to make that work. And it's already confusing enough to begin with with two characters having the same number. The E in the numbering scheme isn't something like Alpha or Beta as a letter(something easily done to help differentiate unique costumes, etc. While it is the Epsilon letter as well in one language, it's basically an apostrophe-like letter in Japan). It's actually an outright single letter that stands for Echo. You can't have two Echoes here. In addition, even the website designates it in all languages as NumberE for the page number. They keep a particular consistency in that regard. Besides that, no other clone type has ever been given a designation besides "yes, this is how we developed them" and is more of a fan thing. The closest is when they put the clone next to the fighter, but Brawl started to tune that out and it's hard saved for Echoes only now.
They clearly designed it for one Echo per fighter, and it makes sense. It's also a good system that keeps it simple. Which is the point. Dash Fighter(the JP name) and Echo(the English name) work wonderfully. It's a deliberate choice regardless. Like, the Fire Emblem joke is fun and all, but if it's making people entirely misunderstand how the system works, it is doing something completely wrong. But as I said, Proto Man having what is clearly some more unique properties would just throw him into a regular clone status anyway if they want Bass too. Both can work(Bass moreso), though Roll is not possible due to what I said above. Ironically the Legends version is far more similar to its own MegaMan, but they're really damn different in Classic(Proto Man is potentially different enough, and Bass is just MegaMan with a new headpiece). Do remember that the core is how much their bodyshape is the same and if any unique properties are given and to what degree when it determines how much an Echo Fighter can be. We do know if attributes change too much, that alone can remove the status. It may not be entirely why Dr. Mario is a regular clone, but it's also worth noting that his attributes make his tier placement significantly further from Mario than any other Echo Fighter too, showing that he's quite blatantly more different than Ken in full practice.
Fair on Proto Man, but it's not just using the Shield alone. It's how it's defined. Also, if he's constantly able to have special shield properties, he'd be unlikely to get an Echo status at that point. That's some massive gameplay differences in practice. That said, looking at Smash Wiki, it's... not very good at some definitions. It doesn't even define Echo that well based upon information we have. Especially being it's a completely different system from the others. Or that it tries to treat someone like Young Link as less than a semi-clone despite blatantly being one in practice(Melee kind of makes sense, but Ultimate he and Link play way too differently from each other. And it's still questionable in Melee to be called a "full clone". The others are close enough to a degree, though maybe not Ganondorf, that it makes some sense). But that's a problem with a fan wiki as well. And moreso defining it by fan stuff and less by more proper terminology, heh. Echo Fighter doesn't even have its own true page, for some silly reason. Though to be a little fair, most of it is based upon exact data on how their definitions are(which is still arbitrary, but it's not some random oddity. To lightly clarify, Young Link only really holds a true clone status due to sharing enough animations with Link to be over their defined percentage of what counts. Again, it's absolutely arbitrary).
But anyway, it's an awkward thing otherwise, but it's pretty much clear it's currently designed to have one Echo per Character max. It's absolutely changeable, of course, but at least it wouldn't work right in the current setup.
Also, yes, it's possible for Proto Man to be an Echo. Obviously he can perform the same moves. It's just that it's quite clear we get one Echo per fighter. Since one has a unique Shield, it's pretty obvious Proto Man if Bass was also there, would be the deliberate clone choice since it's easier to work that way. That said, if Bass was given more unique properties while Proto Man barely used his Shield, they can pull the opposite too. It's really only Roll who cannot hold an Echo status at best.