It's good to see someone finally motivated enough to perhaps make this happen (it didn't before and yes the OTC stuff is just way too hard for most people).
For this to work best I would recommend that it be documented in an open way so that hopefully down the track other rating sites will use the same implementation (rather than ending up with multiple incompatible ones) and I see such rating tx's as having far more value than SD tx's do.
![Smiley](https://bitcointalk.org/Smileys/default/smiley.gif)
If the rating data is view just as being data (which I would recommend) then cram as much as you can into that (and as many different types of things such as id verification level) then the website's success will be in simply and hopefully powerfully being able to let you "view" a buyer/seller without having to understand the low-level stuff (although important for that to be available for other sites to display also so you can be assured that the website isn't misreporting).
Being able to "filter" out buyers/sellers based upon their obscurity (for example) would be a nice feature for the website to contain.