This isn't a QT7 thing. It's been that way ever since QT4. Only the Pro version has any useful features. Which is utterly absurd. Encoding and conversion is one thing, but full screen mode? Since when is watching movies a "pro" thing?
But there's nothing forcing you to use QuickTime Player. There are plenty of QuickTime players (not the lowercase P) out there that support Full Screen Mode. AFAIK, QT Pro doesn't add anything to QuickTime itself, just to QuickTime Player.