My MacBook Pro (Early 2011) was a major catastrophe after Yosemite, and Preview has been one of the biggest offenders.
I upgraded my memory (Yosemite was most definitely NOT made for machines running 4Gigs of RAM ) and installed a Solid State Drive (SSD) that handles memory swaps much more efficiently.
That solved most of my problems, including persistent Preview crashes when I put the app under stress. Which is kind of counter-intuitive, as the Activity Monitor only showed alarming stress during kernel panics. Still, if it works....
Preview still shows twitchiness with large, edited .pdf's, and there's no question that the engineering on the Yosemite-build is horrible. It stutters when I scroll at times, but not so badly; annotations are cumbersome (and don't play well with Adobe standards), but they don't get hung up thinking about it nearly so often.
I have a lot of muscle-memory that gets ready to do a hard shut down when I load a big file and see the Beachball. But files that used to crash the app no longer do.
Your mileage may vary, but memory upgrade worked (mostly) for me.