I don't have much of an idea, but I've given it some thought anyway.

I think that the mining process via the Proof-of-Work is the optimal safeguard in the distribution phase of Bitcoin. In this way, Bitcoin is distributed in a way that is acceptable to most people. The term mining implies that new Bitcoins are generated in this process. Changing these basics would indeed seem like fraud.

However, it is also clear that the Bitcoin price cannot more than double every four years for all time. This means that fees are becoming increasingly important for miners. Bitcoin loses its distributed nature because nothing is distributed anymore. But simply increasing the Bitcoin supply is not a solution either.

How do we escape this dilemma?

Instead of wanting to rule out 51% attacks, you probably need to think about how to deal with them.

Questions:

• What is the point of a mining process that hardly generates any new coins?
• Do validation and mining have to be inextricably linked?
• If the fees exceed the reward, is it possible to add a proof-of-stake process for validation?

These are interesting mind games. I think we have at least another 16 years before we actually have to deal with these things. But it will have to be done at some point if humanity wants to use Bitcoin permanently. Solutions are usually found when a majority finds a technology useful.