large fees or short block time.
Short block time? No one actually defines the block time deliberately! Fees also don't affect the time between blocks at all! Miners just try to find a new block as fast as possible and as soon as they find one, they publish it. Waiting for more transactions would be very risky, because you would end up risking your block-reward!
And a terrible risk! If you added more transactions, the block would change and the hash would be different, so you would have to re mine the block entirely -- not likely to beat someone else in doing so. A miner also isn't going to waste time NOT mining just because they don't have enough TX's and want to get more fees -- the fees arn't likely to surpass the 25BTC block reward. They will mine constantly regardless of the amount of TX, and will solve lve a block before having many or even any TX that qualify for their miners tx rules..
In the future after all the bitcoins have been released, wouldnt a small block such as this be extremely detrimental to the system? Suddenly your reward is based on the number of transactions, and no transaction = no reward...
The hope is that either (or more likely a combination of both):
A - The price will increase due to no new coins being produced/entering the market and increased use worldwide, making just TX fee's with no other block reward still have a significant amount of value and be worth mining for.
B - Either the amount/demand of transactions will increase and the fee amounts will endup higher out of need to ensure TX make it into a block.
