Diversity is good, although sometimes individual results of diversity can be bad.
As much as I dislike useless reviews, IMHO it would be a mistake to restrict the format in which one may post a review for a number of reasons, as follows:
1. The diversity amongst posts without restrictions often communicates a lot about the person composing the review, which can be a handy indicator of how useful the information might be.
2. I would suggest that enforcing adherence to a regimented format would detract from the various personalities of those posting. Having been around PERB for a few years, there are a number of members whom I could identify their posts even without their handles affixed, and for many of those reviewers, forcing them into a format could be effectively like chopping them off at the knees
3. Again referring to the existing diversity, for myself and likely many others, it can be part of what makes PERB useful. If you go read the many reviews for, say, Maddi 5868 for example, reading many (or all** of her various reviews in the multitude of formats provided, you leave with a much more complete picture of what to expect, as opposed to having a handful of formatted reviews that all say the same thing.
4. Along the same line of reasoning as #3, being forced to restrict one's review to a format, especially a checklist, doesn't account for YMMV; what I mean by that is, two very different individuals can see the same girl and have different experiences, possibly because of their personalities. In a checklist, for example, you'd see two filled out differently, and potentially think, "hmm, inconsistent service", however when it's just a person writing about how they felt in their own words, you can get a sense of who the person is and consider if that might have been a factor in the service they received, even more so should you know the reviewer's style from previous experience. One instance that jumps to mind is a girl seen by both myself and a user "Gp60_monster" (or something like that)
I could go on if you wish, but I think you get the idea. I do have an alternative which I would like to suggest, which would be GUIDELINES. You could write out guidelines of what's expected in a review, and send a copy along with an example of a "good review" to new & existing members, and even add a 2nd "flag" button for inadequate reviews. Perhaps come up with a system where it a review gets 3 flags and it's fwd'd to mods and if found inadequate, returned to poster for revision. Just a thought.
I don't like checklists myself, but I like ludivico's checklist reviews because they're his. Please don't take that away from him or any of us.
Final thought: you want to make a quality of life change on perb? How about DARKMODE?