You still haven't said how it would benefit anyone, there's several in my area that would be top of the list of most reviews but would be of no interest to me.
The way I work is I find one I want to see then check here for reviews and if they're on AW the list of all their reviews is at the top of any one of them.
I work the other way around tbh, I generally start here because here, I get to see real reviews and obviously look for keywords that interest me to find the SPs. Top reviewed SPs would make this search easier i.e. finding the 'best' provider out there approach based on real reviews on UKP, go through the top providers and shortlist the few that works for me and then go to establishing contact from there. I am also based in London and hence the SP base is quite a lot and a top list would help in the first narrowing down process. Obviously, AW allows search based on ratings too, but limited experience has been AW reviews aren't reliable.
Perhaps in the future when software limitation goes away and if the team/user base sees value for this, it can be revisited