I preferred how it used to be. One could select "800-mile upgrade" fare from amongst the drop down menu which included the "restricted fares" option. Now that I am not a medallion level member anymore, but still have more than a few 800 MSUs, I find it hard to book "k" fares and above, since the site doesn't offer that option (default or otherwise) to non-medallions anymore.
(the only option is to select "unrestricted", which leads to the highly priced "Y" fares)