With all sorts of bands reuniting these days (Gang of Four, the Pixies, Dinosaur Jr, the Raspberries) it looks like these bands are on the same path that X has been on for the last few years. X has not released a new record in years and ever since they reunited with original guitarist Billy Zoom, no new material has surfaced. They only tour here and there as each of its members have their own projects going on at the same time.
I think this type of reuniting is a good thing.
A lot of bands think that when they reunite, they have to write and release new material. Well, considering the fact that the majority of the audience wants to hear the material they fell in love with (the older material), playing new material is a little useless. When people see Paul McCartney, they want to hear Beatles songs and some of his stuff from the 70s. He plays a few new tracks from his recent solo album but as far as I know, he doesn't play any older solo material from the 80s or 90s. This makes sense; he's playing what people want to hear.
Reuniting is a good thing: it gives people a chance to see a band that they may have missed when the band was first around. However, playing new material is often a futile exercise. A lot of the time, bands' post-reunion material isn't up to the snuff of yester-year. People want the stuff that is up to snuff. There are exceptions of course (Mission of Burma comes to mind), but most of the time, just stick to the material that people know you for.
I'm not somebody that sits around and wishes for bands to get back together. As long as their music is documented onto tape, their music sticks around.