I don't think so, this would really restrict the manufacturers and make them less likely to use Android. What Google has done is for ICS+ phones they must cont

I don't think so, this would really restrict the manufacturers and make them less likely to use Android. What Google has done is for ICS+ phones they must contain Android's stock themes so applications developed against said theme will look consistent on every device. The manufacturer can still have their own themes, and developers can detect if they exist and use them, but the stock theme must be available.