..Sure smells awfully gishy in here (Half-Orc Eldritch Knight)

[Psyren]

Something changes about the item when the spell is dispelled.

Right, because the spell ended. Not because of the dispel affected the item itself. It's no different than if your GMW had worn off normally.

"Gish in a Can." Distinguishing between proper and canned fishes gishes is an appropriate distinction, especially for how it was used in context. Calling "No True Scotsman" here is like using it when I am saying a dog is not a cat.

It's more like you're saying a beagle is not a dog. A gish-in-a-can is a type of gish. You have yet to produce a definition that says "it it's not 16 BAB and 9th-level spells it's not a gish," but I can certainly pull up plenty of posts where Duskblades and Psywars are referred to as gishes, and Magi too. The community defines terms, not you.