David,
I agree very much with the operational perspective (obviously), but since when in this day and age of infrastructure that size still matters?
Having to change your infrastructure (of any size), potentially with outages and so on, is not acceptable if you are able to design around it from day one.
I see it enough that a member should be able to proactively design their connectivity (should they want to - no one is being forced here) to have the potential for multi-homing.
The silly thing with the multi-homing barrier as Guangliang confirmed, you could multi-home for 1 day and meet the criteria and then disconnect and then you are still allowed to continue using it. So why have the restriction there in the first place?
Surely if someone thinks having an ASN is important in their design, they should be allowed to have one.