There is an ongoing thread on opensuse-factory right now about the announcement to ditch SaX2 from the distro. The reason for this is pretty well laid out in the mail message. Xorg now has vastly better auto-detection capabilities, so a tool that generates a static config isn't nearly as useful as it once was. Especially if its on a laptop that can encounter any number of conference room projectors.
This is something of the ultimate fate of Xwindows on Linux. Windows has been display-plug-n-play (and working plug-n-play at that) for many, many years now. The fact that XWindows still needed a text file to work right was an anachronism. So long as it works, I'm glad to see it. As it happens, it doesn't work for me right now, but that's beside the point. Display properties, and especially display properties in an LCD world, should be plug-n-play.
As one list-member mentioned, the old way of doing it was a lot worse. What is the old way? Well... when I first started with Linux, in order to get my Xwindows working, which was the XFree86 version of Xwin by the way, I needed my monitor manual, the manual for my graphics card, a ruler, and a calculator. I kid you not. This was the only way to get truly accurate ModeLines, and it is the ModeLines that tell Xwindows what resolution, refresh rate, and bit-depth combinations it can get away with.
Early tools had databases of graphics cards and monitors that you could sort through to pick defaults. But fine tuning, or getting a resolution that the defaults didn't think was achievable, required hand hacking. In large part this was due to the analog nature of CRTs. Now that displays have all gone digital, the sheer breadth of display options is now greatly reduced (in the CRT days you really could program an 800x800x32bit display into Xwin on a regular old 4:3 monitor, and it might even have looked good. You can't do that on an LCD.).
In addition, user-space display tools in both KDE and Gnome have advanced to the point that that's what most users will ever need. While I have done the gonzo-computing of a hand-edited xwindows config file, I do not miss it. I am glad that Xwindows has gotten to this point.
Unfortunately, it seems that auto-detect on Xwindows is about as reliable as Windows ME was about that. Which is to say, most of the time. But there are enough edge cases out there where it doesn't work right to make it feel iffy. It doesn't help that people tend to run Linux on their crappiest box in the house, boxes with old CRTs that don't report their information right. So I believe SaX2 still has some life in it, until the 8 year old crap dies off in sufficient numbers that this tool that dates from that era won't be needed any more.