It should be noted that I race in a Fox Mustang, so I don't think it's a terrible platform. And perhaps the fact that I spend a lot of time in it in a race setting makes me less interested in it as a prospective track car.
I agree, there isn't a whole lot really wrong with it, but I'm not sure if it's the best choice for a track car. Then again, as I said, it depends on what you want... if you're seduced by the 302 (definitely a sexy-sounding engine) and the straight-line speed, it handles reasonably well* and can be fun to drive. If your interests tend toward something more nimble, though, you may be happier with one of the more-designed-to-handle roadsters.
* My experience with the handling is with a four-cylinder (with and without turbo), stripped, fully caged, with a coil cut out of the springs, so I'd hazard a guess that it handles a little better than a closer-to-stock version. On the other hand, racing it in a budget series means that there are some nice aftermarket options for improving the handling that are off-limits for us.