You were concerned about Corinna MVP only supporting semver. Please see the README's Principle of Parsimony:
Many things in the proposal are deliberately restrictive, such as Corinna only allowing single inheritance. This is to allow Corinna to be cautious in not promising too much. If we later find this too restrictive, we can allow multiple inheritance. However, if we start with multiple inheritance and discover we don't need or want multiple inheritance, we would break existing code by taking it away. Any proposals to change the RFC must consider the principle of parsimony.
Semver falls under this. If we allow more than semver and it's a mistake, it may be too late to change it. If it's too restrictive, it's trivial to say "we can add support for more version formats."
The MVP isn't designed to take anything away. It's designed to offer something we can play with and find out what works and what doesn't.