Keep in mind that it's even more simple than that. Ness' gameplay is meant to represent the tons of different PSI in the games, despite not using it himself. That's his mechanic. Lucas, as a semi-clone, does this too. Ninten shares the same build as Ness. He makes sense as an Echo, Clone, or Semi-Clone while using the same mechanic of representing the different abilities in Mother. Combined with being a Ness lookalike, he seems destined for an Echo status, and it'd fit the Mother series well. It's very doubtful he'd be heavily unique considering Lucas definitely wasn't. And Lucas is pretty different from Ness too.
That said, my bigger issue is Ninten not having a canon design that's different enough from Ness to help make them look different enough. Dark Pit even looks more different in comparison. It's literally a case of 8-bit VS 16-bit. Or basically comparing NES Link to SNES Link. They're so blatantly the same character design it's ridiculous. Not that he can't use the non-canon design from the commercials(in fact, was that design even owned by Nintendo? If so, there's a small chance it could be used), but that still depends on Mother's owning being okay with that. When they're known for being rather stingy, which is why Mother 3 was never localized yet. Same with why EarthBound took a long time to get on the VC alone. It had a lot of parody music that wasn't okay to use, so it was a licensing nightmare. Itoi(did I say that name right?) doesn't like the things being changed much at all. He's a stubborn man. For better or worse, it's better to expect Ninten's official canon design. Also, for the record, I'm just looking at issues that could prevent the character from getting in. He could easily be unique and as long as you can tell him apart from Ness, I'm fine with it. My biggest worry for Dark Pit was being impossible to tell apart from Pit while in Metal form. They fixed that by having a colored hue on all the Metals, updating their design so it's no longer an issue.
I do more prefer Porky myself, though. I'd love the mechs being used. We don't have a mech user either, so that helps.