1) Routing Table size Is this as important of an issue as it was 3 years ago? Nope, not with M40s and GSRs as standard backbone routes. 100K routes is no sweat with these boxes. Of course, some of the big carriers would have to finally replace some of those older 7505s floating around their networks.
Route and forwarding table memory and processors speeds are pretty much the same between GSRs, M40s, and 7500s. The packet processing capabilities are where the relevant differences are. As for if it still matters, well, the fact that it takes > 4-5 minutes for some routers to pickup a full BGP table from a single peer, or generate the updates to send to a new peer, well, not worrying about this sure isn't going to increase network availability any.
2) IP Address Space Scarcity There is no real address space scarcity. We still have most of 64/2 to go through. And there is always an easy answer to this "problem" - turn IP space into a commodity and have an exchange system where folks purchased address space from each other. This would result in the hoarded "class A" space being thrown back into circulation, as the companies that had them would have an incentive to unload them - money. As IP space is really not that scarce (and would be less so with the Class A's in circulation), the prices would be reasonable. When they became unreasonable, there would be a market-driven move to IPv6. Ah, capitalism.
The answer to most of these issues is to allow much smaller allocations in a specific block - say 65/8. Allow /24-/21 allocations in this block for smaller multihomed enterprises. Then, start cracking down on the other blocks by filtering smaller prefixes. This would enforce necessary aggregation where possible, but still allow multihomed enterprises to obtain an appropriate amount of IP space on their own.
I'd venture to say that if routers were capable of maintaining 100K+ prefix filters, and secure, reliable registries were available to populate the filters, and these longer prefixes (/21-/24, or maybe even longer) were allocated and registered in a reasonable manner, and tools were in place to efficiently manage all of this, and again, the routers were capable of handling all of this, well, I doubt Randy or others would have as big a problem accepting appropriately identified longer prefixes from peers. Of course, until the fairy dust is sprinkled over all our networks and these things are no longer a problem, we'll just have to deal with them, in the way that the individuals, and their employers see fit. -danny