It's been a bad sign, for me and many others. Before 10.7, OS X 10.X development varied between 1 ½ to 2 ½ years with biweekly or weekly releases that required downloading a .dmg from the developer site, burning the image to a DVD, wiping the system and installing a "clean" OS. This allowed for improved debugging by eliminating any possible third party app "contamination" (10.7+ releases have proved difficult to properly isolate any system matters), and allowed Apple more time to "get it right" before release. Of course not all 10.X first releases were stellar, but they were far better than the current annual release cycle to match iOS. There is no need to rush out annual OS overhauls, especially as we're just on 10.9.3 beta. By the time iOS is released it may be .5 or .6.
Personally, while Craig Federighi is an excellent engineer, nothing beats the work Bertrand Serlet did while SVP of OS X engineering. I still believe 10.5/6 are the best OS X releases to date (and before the "Serlet was involved with 10.7, he was not, he was already on his way out the door to Parallels 2009-2010, 10.7 was all Federighi).