This was suggested a few times because people do not like doing their research first. This is problematic:
...increases the orphan rate, thus increases the amount of hashing power wasted. It also changes everything people have learned about confirmations, because now 2 confirmations provide the security of 1.
Although, I recall reading some research 'paper'(?) that stated that 7-8 minutes would be the optimal time for Bitcoin.
The block time is not the debate we are focusing now, just the blocksize.
There will be a block size proposal in < 3 months.