Well, there are other instances in the main Tau codex where special characters have signature systems that are particular to only that 1 special character (e.g. The Dawn Blade)... why wouldn't the same be true here?
It's a number of reasons that I think this is very different than a SC's wargear. For one, such as the dawn blade, it's listed under that character. For another, NONE of the rest of "the 8" have either unique wargear or rules -- it's all just a combination wargear along with IC status. Signature systems abound (most of it from old Tau, the 8 are old, from before Farsight broke off) but none of it is unique.
There's also just fluff descriptions --It's not described as a piece of gear for O'vesa specifically, nor even one type of suit. It also modifies the WS to 1, for an SC there would be no need to do that.
It really looks like they just forgot to add "riptide's can take this".
I would agree if you take "the 8" and they have signiture systems then that would stop you from putting on generic commander. Unless there is a rule that allows suck things.
Meh. I'm kinda ambivalent about this, honestly.