The confirmation time won't change, by design, but there are risks.

It seems that the risk of a double spend attack is increased.

If the price dropped precipitously and enough miners dropped out, a block of miners could purposefully turn on all of it's capacity, operate at a loss, and take over the network. Other miners who had dropped out due to economics wouldn't have an incentive to compete. In fact even the miners that hadn't dropped out might at that  point drop out, leaving the single entity (operating at a loss) as the sole mining block.

Does anyone else see this as a possible threat. Does the protocol deal with this?