We were discussing this internally about 2 years ago...
However, what seemed to be a brilliant idea turned out to be quite questionable... the problem is that most people IMHO don't want to see similar "magic" because they don't understand what's going on... Basically, the feature would require some comprehensive GUI to let the user be informed (but not scared) about what's going on...
Maybe for avast 5...
BTW the number of questions related to "how do I insert the license key to avast" has dropped quite a lot recently, so it's really a big issue anymore...
Thanks
Vlk