«issue for end-users» It's not really an issue. End-users always have the possibility of running in SPV mode where they don't download full blocks. «They'd be

«issue for end-users» It's not really an issue. End-users always have the possibility of running in SPV mode where they don't download full blocks. «They'd be far more likely to mine on top of an old block» Not really. First of all, a 1GB block today would be transmitted in typically only ~12-15MB thanks to Compact Blocks (6 bytes per txn ID). Graphene would cut this down to 3-5 MB (http://forensics.cs.umass.edu/graphene/ http://forensics.cs.umass.edu/graphene/). Secondly, with current software and current hardware, we can still bump the block size ~100× while keeping the block verification time low enough that it's still workable. Then with software optimizations and another few years of technical hardware and network bandwidth improvements, we can get another 10×.