...Those aren't "unique features". Those are features everybody have. Remember, he's not the only Mario contender under the sun. Every single remaining Mario character(or at least a bunch) can use said features, so they don't make him stand out directly from those others. Even if it's, say, Waluigi and King Boo. Who both can use same said abilities. This is why it's a detriment. It's not an ability that's specific to him within his own series. While it's not saying it's a bad moveset idea whatsoever(no, they're great ideas!), it doesn't make it an ability specific to him and only him. It's actually something Sakurai talked about during Brawl, when choosing various characters. Of course, that doesn't mean it applies to all, like Echo Fighters, or any general Model Swap Fighter(clones, semi-clones, "barely count as a clone"(for this last one, this applies more to ones like Wolf or Ness, who both use a core base instead of borrowing a few moves, but blatantly are highly different from their parents Fox and Mario respectively).
Of course, there might be a move exclusive to him besides being a reasonably good jumper in Super Mario Bros. 2 USA to look at(which to be fair, the "charge up to jump high" is something all can do, yet was given to Luigi in Super Paper Mario. So it can happen... at least in some Mario spin-offs. I mean, does anyone know of an ability he explicitly uses that nobody else ever has. Or even just the basic Toads only, of which he's not that much different from besides being a different person? I'm curious on that front. Although that's kind of why Captain Toad has a lot of support behind him. He has some stuff more exclusive to his design, not even just limited to how his weight would be logically different since he's meant to have trouble jumping(sometimes not even allowed to, heh) due to his weight of his backpack. But also for gameplay mechanics. I know that Captain Toedette does this too(part of why she's suggested as a possible alt. Though logically normal Toadette makes a good alt for Toad, assuming that her unique hair wouldn't affect the model. And it's not like she couldn't work as an Echo Fighter... as could Captain Toadette for Captain Toad. Why yes, that's 4 potential unique characters in some way, heh). But you get the core idea. This is why I'm not that surprised he has yet to make it in(regular Toad). I want him in, but as long as he lacks an exclusive move, he's far harder to look at from the current perspective. And since he's not an easy Echo Fighter material anyway, that also doesn't exactly help his point. They also kind of are odd on the Toad Guard move. It's very clear in the Japanese wording, but the actual Trophies do nothing to specify which Toad is being used as a Guard. However, to be fair, they all look alike so it's not like they can't just change the name in Japan slightly, to Kinoko Guard.
As I've said before, Chrom is not in the same position either way. He's just a quick summon as part of the overall Final Smash and plays a very small role in it.
However, as I said above, the issue isn't that Toad is part of it anyway. They can literally do the same move and change it slightly in Japan to specify it's a different one. Or even change it to a Yellow Toad or something. The issue was always "what is his personal move that we can start looking at to make a coherent moveset out of", as he obviously wouldn't be an Echo or clone. He's too different in bodyshape to do more than borrow animations(and obviously Turnips don't require extra work outside of Toad having... obvious animations added. Any parameters are pretty easy to fix up). Having more Super Mario Bros. 2 USA abilities sounds cool too, as we don't have a charge jump specifically, and while it's not completely exclusive to him, it's still neat.
Incidentally, I still don't know if the Japanese Toad Spirit is named after Kinopio, the character, or Kinoko, the species. MarioWiki, while often reliable, doesn't list the actual Japanese wording, soooooo. Hard to say. So either it's hard to tell or Smash Ultimate made an easy error, heh.
Those sound like cool ideas.
Toad's odd cause the trophies don't imply it's the actual main Toad, though the official Japanese name makes it clear. Kinopio Guard.