Yeah, when I think of 'test standards' I don't really mean what's written, because as you point out, that's just a list of techniques. But there is a standard still (at least within my dojo there is, with rising expectations for each rank), it's just that it's not necessarily formally written down, perhaps in part because it's much harder to express clearly in writing in unambiguous words? That's much harder to maintain consistent between different dojos, and it really has to be clearly and firmly in the instructor's head. I guess that's maybe one of the reasons you do see unprepared students at seminars being recommended to test sometimes.
For us, the hour requirement is there because that's when they think that you should be able to do what is expected of you, which happens to coincide with the rank. It's not just a number that when you reach it, you're asked to test. Someone could come randomly for two years before hitting 100 hours and still not be invited to test.