@Dydymoon there is two options after the minted tokens end, either focus on distributing fees or fees and introducing an inflation schedule, however I think that will be for years to come since the current Aave Reserve should be sufficient for LPs over time and currently I think the consensus is that the initial distribution would apply for first quarter and then new allocation could be scheduled.
@Lance yes I think if the rule is only based on utilization rate, it would be gamed quite harshly and would max the utlization to the extent that it would be hard to exit the deposit position, creating some liquidity risk. I like as well the retroactive multiplier as it allows stakers and LPs to build their liquidity and retain their position that they achieved over time. It would be good to check the technicalities on the implementation but seems to be as you said, the AMPL model with extended period that increases over time.
Whats interesting is that it ties up the staked AAVE and also the rewards AAVE for a time period, so it brings more safety and also utility for governing the protocol.