As a protocol rule?
I find that worse than an automatic adjustment of the max block size. You can't set prices like that. You can't predict what 50BTC will represent in the future.
No, it does make some sense. With this type of system in place, the security of the network would be based on a BTC based reward. This way we would always have similar security level
relative to the actual value of the monetary base.
You can't predict how much the monetary base will be worth nor how much security is enough. You can't set prices like that.
I do agree with Mike again that it's a bit questionable to just set it at 50 BTC. We really don't know how much mining is "high security", we only know that what we have now is quite enough. It would be wasteful to pay more fees for more mining if we don't actually need it.
That's what I'm saying, you can't know what's enough or more than enough, so you can't simply set a mandatory amount per Mb.
You seem to be contradicting yourself in the same post...