I like that. My main complaint of auto-renewal is that I keep replacing 737's and 767's, and the 747's and A380's get older and older for cash flow reasons. So logic point 1 makes me happy.
For renew in Y weeks, am I right in assuming the money would be spent the next cycle, and plane arrive Y weeks from that cycle? Same as purchasing a new aircraft? Again, cash flow, and when cash is available, becomes a significant part of the game / planning process.
One thing that occurred, perhaps the ability to set a universal replace percentage, but be able to override it for an entire model or sub fleet? I'm thinking that my Embraer's could get replaced at a different percentage than my A380's... or my 767's doing intra-africa turns could be replaced at a different percentage than my Japan - Middle East turns. Not actually sure I'd use that, but it'd be a way to allow further customization and tweeting in the game.