Here is a real newbie question. If the current 1Mb blocks are underutilised, is there any evidence that doubling them to 2Mb will make any difference at all?
The two major sources of under-utilization are empty blocks and pools which are using the 750k soft-limit. This is a small (but significant) fraction of blocks. The rest are mostly full and the network would definitely benefit from having some overhead to work with to avoid transaction backlogs.