The fact that most people seem more interested in arguing about Kaneda or laughing at the press release seems to undermine the level of excitement a blockbuster announcement like this is supposed to stir up.
It just seems like a strange move to me. It addresses a "problem" I wasn't aware JJP had - lack of name/established pinball designers. And as many have pointed out, SR's layouts (let's face it we all know what to expect at this point) don't really seem to lend themselves to JJP mechanics. Most JJP fans have been trashing Steve for years, I would not say there was a groundswell of demand among the JJP faithful for this move.
I'm not sure who really gains most from this event. It's not really moving the needle, "need another established pinball designer" is about 22nd on the list of needs/issues most of us would list for JJP, and Stern seems to have plenty of fresh talent able to crank out games in Steve's absence and the resources to recruit or develop more young staffers.
Time will tell, but who really won this Monday?