Same here. I rarely see any proc and if I do, it's on the stuff that really doesn't matter much. Living Steel procs have become more and more rare and the same seems to be the case for pots and flasks.
I haven't read about a stealth nerf to the proc chances but everyone with Alchemy I know, has been reporting the same thing. At the beginning of MoP, the proc rate seemed much higher, once got 5 Living Steel in one proc and 7 Trillium Bars in another for instance.
Only reason I keep making Living Steel, is to make some gold at the beginning of 5.2 with the new BS patterns.