I think that would be futile. Because the exhaust is mainly stainless and not necessarily symmetrical, it would be hard to cut it just right and harder to reweld it so there were no leaks and it's possible to end up with an exhaust less efficient than what you started with. On the other hand, some people who don't know what they are doing simply drill holes in an effort to make the thing louder. People who understand the technology of exhausts know that louder doesn't = more power.
Agreed - the increase in power is only ever going to be marginal. I can't see any point in removing the cat; far better to replace the whole system if you want deeper sound and tidier looks - just don't expect much difference in power.