If it was actually a good defense, you'd see it more commonly as a base defense.If you have a Grubner type at nose, which it sounds like Illinois does, the 3-3-5 is a great defense. It's all about personnel. You have a short memory. A nose who stuffs the A gaps allows the rest of the defense to scrape anywhere on the field and it's very difficult for pulling guards to get out in space to block it effectively. Plus there are so many stunts that are used out of it to confuse blocking schemes.
None of the elite schools do, and of the schools that run a 3-3-5 as an occasional package, none of them run it the way that UM has the past few years. Any defense is going to do well with a good nose tackle, but there are other defenses that can help with other shortcomings more than the 3-3-5 that Bobby runs does.