I'm not quite willing to commit to that as a trend for JTRPGs, although I see where you're coming from. I'll have to double check if Princess Wing has anything about switching up the default flavor (which admittedly is invoking heavier armament than typical mahous)
Ah, fair. I'm probably jumping the gun. As for Princess Wing - it doesn't mention changing the setting flavor, per say, but on page 22 it mentions that the default setting contains Princess Cores with a "transformation hero" like designs, even though frilly and feminine is the general social norm:
Due to the policies of development companies and nations, most Princess Cores are announced with elaborate decorations under the label of “for women,” featuring cute (or beautiful) designs. However, being a Princess does not necessarily mean that one must prefer highly decorative designs. Some individuals may lean towards streamlined and sporty designs, robust and weapon-like aesthetics, or even designs reminiscent of transformation hero suits.
There is an extra twist to this particular game that I think supports your broader genre-exists-within-a-context point. The mechanics for this system were adopted from an Evangelion fangame, so, I doubt the designers were thinking of magical girls as a totally self-contained thing.
The mahou/mecha overlap is another thing I don't really see talked about much, even though I get inklings of its existence: Princess Wing's whole schtick, this game being effectively a Precure fangame adapted from an NGE fangame, and in the 2000's Nanoha wearing its mecha influences on its sleeve. It would seem, at the very least, the genres' fanbases in Japan have decent overlap.
