If you are an HP user because you want stability, then the wait for ghc-7.6 was just long enough: There was a critical bug fixed in 7.6.3 which was released just in time for this HP release!
We do not release HP for every GHC update for two reasons: 1) Most GHC updates are not in the stability category that HP strives for, 2) Often new GHCs require minor updates to other packages in the HP. The revving of the whole kaboodle more than twice a year is far too much work than the small volunteer group can handle!