The sudden increase in the hashrate makes it evident that ASIC's are mining ITNS now and it's something that needs to be dealt with asap. 14th May is a month more from now. Just imagine the effect of ASIC's in a month. The difficulty will rise so much that it will be difficult for small miners to sustain.
Difficulty retargets pretty quickly, it doesn't need a month.
The reason we didn't set a earlier date for the fork is because we are rolling out a bunch of blockchain features that need proper coding and testing, all consolidated into block version 4. This is to avoid multiple painful hardforks.