Just thinking out loud here, and this may have already been thought of and dismissed.
Addressing both decentralization and disbursement of new coins, why not make every single node in the network a block producer chosen at random? The owner of that node gets to keep the new coins and select the next block producer at random. Only one node at a time will be selected as a block signer / producer, and which node chosen is non-deterministic.
The algorithm that decides which node is next may be the Achilles heel of this idea; it may just not be possible to create such an algorithm in a secure, truly random way. There would have to be some way to insure the code of every node does not get corrupted. It's integrity must somehow be guaranteed, since the security of the network resides in the security of every node.
If there were a way to create a unique mathematical signature of the code and the machine it ran on that could be easy to verify but difficult to create and counterfeit this may be possible?? Might it be possible through a similar manor to how the earliest blocks of the blockchain become more secure as new blocks are added?
Like I said, just thinking out loud.
If it were possible, it would incentivize everyone to participate as it would constitute a type of lottery.