I think wizard and Plank have some good points, but as to "what" meets the "standard" of RLC may differ between many of us...specifically with regards to personal tastes.
If RLC is going to continue being a project (as they call it), then RLC may not continue on a path to remain what many of us consider RLC to be...a voyeur site. They could easily shift towards something "similar" as chatterbate or another like site...something along the lines of controlling the environments and/or couples' actions...perhaps with or without interactions with the cameras. Hopefully they won't, but it's difficult to predict the direction and goals of RLC.
Personally, I hope RLC gets back and stays on a course to offer us a voyeur site (as this is a pretty rare site with the quality it offers). And, I don't mind the occasional signs when the tenants communicate with us...as long as it does not turn into habit.
As to the types of tenants they offer, being attractive, thin, young or whatever is just a plus. I only have one criteria that the couples need to meet in order to keep me watching and keep me paying. Just be INTERESTING.