I've found the whole discussion and debate really interesting, and there are a lot of things that I've learnt over the last few days. One of these is that many blocks are submitted before they are full. So instead of increasing the capacity of blocks, why not ensure that the capacity is utilised more efficiently. A minimum size for new blocks could reduce the current block problem, and leave the blockchain existing in its current form. If the restriction was only imposed on new blocks, then all existing blocks would remain valid.
I'm not sure if that's do-able. Even if, what would happen if there's a period of low activity (few txs made), not enough to fill the block to min size.
But most of all, at what size would you set the minimum? If you set this at 0.5mb them miners could just limit themselves to 0.55mb etc. So for that to work, you'd have to set the minimum pretty close to max block size and that's not feasible.
