however, due to memory restrictions, we cannot hold data for two types of animation
Really? Memory restrictions preclude you from having one OR another animation in use at any given time? If you change the setting and remove one from main memory you can then load the other. Only one needs to be in main memory at any point in time. I don't think people who don't like the new animation want to mix-and-match so a all or nothing swap would suffice.

Now, if you meant "storage" then tell the PS3 kids to get bigger hard drives.