Except, as pointed out, it existed before that, with the text being clear. So I assume its not a "standard upgrade".
Already addressed that in the very section you quoted.
The initial upgrade may have simply been an upgrade to team equipment, simply in that it would have given better weaponry and armour, the effect of which was then increased by looking into prototype armour.
It's a possibility, anyway, but we don't know enough to say for sure whether Progenitor Frames has anything to do with the equipment upgrade. It might just be 'better guns' or something.
Except everything we've seen has indicated that XP only affects Nepgear, and more importantly, we know that the improvements and upgrading of other characters is story-based, since
@crystalwatcher offered to give us control of the others instead of it being story-based(which we refused).
Well, we
know that it isn't an ability; the description text in the shop doesn't mention granting an ability, like it does when the option gives an ability, so we can rule that out.
Aside from that, what could it be but an upgrade to their equipment? They're our team; spending XP to upgrade them is perfectly reasonable because they are effectively one of our assets. Much like our weapon, they aren't actually
us, but we rely on them and in a sense they 'belong' to us.
Remember, XP is a way of abstracting
improvement. Improvements to the team leads to improvements to our combat effectiveness as a whole, so paying to improve them makes sense, mechanically. After all, we gain from it. Insisting that these improvements can only ever apply to Nepgear seems like a big assumption to make without something solid to back it up, like WoG.
Character improvements, like them developing their abilities further, are story based and something they'll do on their own (and something we can help with through our actions), but obtaining better equipment for them is clearly within our purview. Not
all upgrades to others have to be story based.
I never said it was cool, I said it was likely. The text reads "Improve Team Equipment". If its not the ability to generate new equipment, or obtain new equipment, it would likely mean that the equipment is upgraded. Since we know that upgrades to others are story based, its most likely something to with Nepgear.
And it isn't. Likely. At all. Not even remotely, in fact.
It's a fair guess that the reequip option involves getting better equipment in one form or another, and definitely not through any ability of Nep's. Ergo, we're probably just procuring better equipment for them in an entirely mundane fashion, Progenitor Frames may be involved.
What is even your argument here? You seem to be trying to put forward that Reequip must be an ability, rather than simply obtaining better equipment for them, but all the evidence is against that and you've offered nothing in support except half-baked chains of nearly inscrutable logic.
Reequip is almost certainly just
getting better equipment. That's what it is. That's what it does. We have no reason to think otherwise. This is a stupid argument.
Because people refuse to gamble with this.
We're low level. Give it time. The mystery box option is alluring, but right now we're still in our infancy. We can't go around spending huge chunks of XP for entirely unknown gains.