....but that's sometimes not the case. In fact, for the very reasons you're detailing is a good reason 'why' it would be a good idea. I understand that there are "natural reasons" for the YMMV factor. But there are SPs would claim to be 'non-judgmental', so the burden would be on them to see how 'judgmental' they claim they are not.
That said, I'm not suggesting we all give our exact names, our exact age, our exact race, where we work, what's our social insurance number, and what we had for breakfast this morning.....just ballpark idea as to the type of person writing a review.
I could see it were we in an arena where, say, it was a high school class promised that they would be graded on a true curve, with as many A's as E's, and as many B's as D's... and with, say, 60% of everyone destined to get a "C".
But psychologically, you are already in an arena where the vast majority of all reviews will be favorable (and it is a self-fulfilling prophecy by PERB, because they put the reviews here on display to effect that outcome)... so the best thing you can do to optimize the chance that you and your next SP 'connect' spiritually right AT the same level from the get-go, is to
survey numerous reviews of hers and numerous ads and online posts of hers.
Mathematically speaking, as the number of unique reviews you read about subject Y approaches X... the less important will be the specifics of any one reviewer (won't matter if he was a mailman, or a milkman, or a bulldozer driver).
IF on the other hand you have but ONE review of someone, and had to make it, or break it, based on that one review... then it would make more sense to need a basis for that one person's qualifications for reviewing.
The stupid complaints on these boards by people who think "waaaaaaaaaaaaaay too many of the reviews are unbridled positive reviews" are FAR more numerous than are inappropriate reviews. They just can't seem to ram it through their heads that
A ) Most reviews are written by a man who recently had sex with an attractive woman
B ) Most PERB reviews are written by a man who spent a decent amount of time researching on PERB or elsewhere and then selected that woman based on details which mattered to him
C ) It IS sex... it isn't a new toaster from a company that guaranteed your toast wouldn't burn (there's gonna be some arousal - unlike with burnt toast)
D ) There is a giant 'margin for error' involved (even mediocre sex with a hot, young woman is a pleasure)
Of course there are handfuls of implied expectations (she will have the condoms, is prominent among them) (she will be sober and expecting sexual intimacy) (she will be available somewhat on time) ... which, if not met, quite often draw the written reviewed ire of the fine consumers of PERB... but aside from those black-n-white issues, it is already likely to be a pretty good experience going in.