Yep, it wasn't a good idea for pattern because the interest is in larger planes. Pattern contests are getting fewer and farther between and in general are suffering from poor attendance. If pattern allowed larger planes that could use gasoline burning engines, they might see some growth in their sport. As it is, pattern requires an $800+ investment in engine and pipe. For that kind of money, you can buy a nice 80cc gas single with muffler. And you don't need to throw $20 toward glow fuel every flying session.

For Imac, the less restrictive the rules are, the better. Expensive planes don't win contests in any class. It's good pilots and practice that wins. Think of it this way. A Steinway piano doesn't make you a musician.