Historically - this is my impression anyway - when a site has its own reviews, TER cuts them off.  (I can think of one obvious exception with respect to our proclivity here!)
Second issue (I'm wild ass guessing) might be that their main revenue, or at least a significant source of their revenue, would be coming from the ladies posting ads on their site.  A discussion board such as you're suggesting might turn off some of the advertisers.  I'd guess it'd be just a source of heat and hassles for them.

Mostly, I rely on TER for this sort of information.  I've not found much value in other review/discussion sites.  (I dearly miss redbook though!)

I suppose someone could mount an effort to create such a discussion board, but dealing with censorship, the law, and all sorts of moderation headaches would, I'd think, make it well to much hassle to sustain.  Like I used to bop around on Reddit, and could kind of imagine a subreddit dedicated to "Discussion of advertisers on tsescorts" but it'd be shut down within days if not hours - even if it was a "private" subreddit.

These days, I seldom bother with ladies who, though they have enticing ads, have little in the way of reputation, which mostly means a nice set of reviews here.  But sometimes I just search this forum and find some gold.  There's a hot looking/sounding one in Oakland who has been tempting me for months/years, but has no reviews, and when I searched the forum here, I found something like "... she doesn't like reviews, but she's pretty awesome!"  So she's on my list now.

I took one for the team just before covid came along, and I ended the review with "... it may be quite a while before I TOFTT again. I'm SO GLAD TER is back!"