>GNU cat has 11 more options than POSIX requires, and if you read the spec, at the bottom it says that those options were omitted from the standard because they can be duplicated with sed.
So, what's going to be a worse waste of resources when you need one of those options? Just running "extended" cat, or running both cat and sed? And how much waste are we actually talking about here? Have you ever sat down and done the math? What platform are you targeting that this would actually gain you something?
Surely you'll have pondered these questions before undertaking such an ambitious project.