This is essentially the Italian model of regulation, or at least the outcomes would be. Ever notice the quirks of the Alitalia program? Miles don't expire, the entire program does on a given date declared in advance. Award charts rarely changed because of the hoops you'd need to jump through to do it - I'd speculate that's why their recent devaluation impacted partner redemption only.

Personally, I like it. I'd rather know in advance that everything will be gone on X date every 3-5 years, but that within that span, there aren't any moving targets.