Sounds like you need to fork and start your own coin/chain. Bitcoin is not easy to change on the base protocol level(/b], if there is any contention it will not be adopted, the idea of making backward breaking changes as you describe and introducing proof-of-stake is not a subtle change and has no chance of being pursued.
There are parts of Bitcoin which have become ossified, that are close to impossible to change even with consensus, if not impossible. Changing those parameters would be breaking the protocol, and how everything has been sticking together.