I concur completely with your thought that there ought to be a way to communicate warnings or kudos, and understand it could open a can of worms. It's why I appreciated Steve Overbury's praise of Barrie Parker, and added my two cents when I thought it was appropriate. fivetsrapens is also very diligent in its descriptions. Interestingly, I've never bought a pen from either. I have bought pens from Teri Morris at peytonstreetpens, and find her helpful and friendly, and am glad to say so.
For those of us who have been around collecting, and these boards, for a while, I think we kind of have a responsibility to at least provide back channel references or criticism. My candor has alienated some - at almost 75, it hardly bothers me - and I have no difficulty debunking some of the self-proclaimed "gods."
My health doesn't allow me to go to shows as often as I'd like, but I like pointing out someone like Bill Zeeble if I am asked about someone who can help with a question about vintage flex, e.g. My greatest joy is when a munchkin, dragged along, stops by and sees something I have in a color they find attractive. Nothing I own is so valuable that I can't gift it to a kid who invariably hugs me in return. I have several multiple-year huggers at this point, and this year, they'll get the pick of anything I have! There's a story there: my own daughter is 22, and we've never met. We plan to remedy that in 20 days (19 and a wake-up for those who are ex-military!). I may be a curmudgeon sometimes, but also a softie, too.
Anyhow, thanks for your wise words.