Miners jumping on and off with massive hash basically 'Diff Jacks' the Blockchain whether purposeful or not. The hard fork was supposed to fix the long Block Times but because the network has had so many miners jumping on and off its been hard to determine the proper results and if your suggesting another Hard Fork, its best to determine the full results from the first one before even considering another Hard Fork and as a rule Hard Forks are only to be carried out as a last resort.