Hi @tinom9 thanks for the feedback 
The ERC being in final stage there cannot be any modifications to the interfaces anymore.
What you propose could be done, but it doesn’t really bring additional (missing) features that would make the ERC-3643 standard not usable for specific use cases, it would just simplify a bit the interface but at the same time break the standardization (as dapps developed to manage ERC-3643 would try to call isVerified() on the Identity Registry for instance. Therefore i don’t believe it would be desirable to make another standard, as the whole point is to standardize as much as possible. To be clear, the interfaces of ERC-3643 are probably not perfect and could be simplified, but the added value of standardization, i believe, surpasses the desirability of simplification/optimization.
I already had the same thoughts about the fact of making the Identity checks part of a compliance module, it could indeed make sense and be doable, but it would break backwards compatibility with ERC-3643 without adding much added value outside of code simplification.