I could have kicked myself for not buying AMD stock years ago, even joked about it with some friends at the time but couldn't afford to take the risk. The reason was (rightly or wrongly) Jim Keller returning to work on Zen.
He's worked on a few different and really exciting things since, but he's at Intel now. I suspect they'll sort it out and turn things around, but running their own fabs is their biggest problem now. They aren't competitive with TSMC and they desperately need to be.