This becomes a game of statistics.  You want a larger pool as it would decrease our variance or  inconsistency of blocks.  I believe when I was talking to Kano, he said our pool size needs to be 5% of the total bitcoin hash rate to bring it statistically within the parameters that would eliminate the long periods of time that we go without finding a block.  Another way of looking at it, is right now if you plotted our blocks on a chart you would have huge spikes and then nothing (for the hours we wait in between) for a time another spike and so on.  At 5% we would have a more consistent smooth line.  Yes we would all sacrifice rewards per block, but make up for it in multiple blocks per day.  In the end of the day, you would make as much or more with a larger pool.  Right now to hit 5% I believe we need to be around 220 PH and that is a moving target as the network grows.