Bitcoin would be more efficient as a Proof of Work/Proof of Stake hybrid, in which the miners & the full nodes share the rewards.

This way, there's the thermodynamic security, plus an inventive to keep your node running & HODL.

Reaching consensus on upgrades would also be easier, and non-mining nodes would matter more.

Preferably, such an upgrade would also restore CPU/GPU mining to allow anyone to participate.