Well, they've not been working on Vita since 2013, nor PS3 since 2013 either. I do feel it's been a pretty poor showing from their PS4 output so far and I do pretty much put that down to Shu. While I think he's a nice guy, I don't think he's especially good at his job.
It's only in the past few years I've noticed it too. Stuff like putting all those games out on PS3 in 2013 and now the somewhat lack of AAA first-party stuff on PS4. Funneling money into The Last Guardian yet cancelling stuff like Eight Days to have London Studio work on whatever flavor-of-the-month peripheral is out, despite the fact that they'd shown themselves perfectly capable of making non-gimmick stuff. Inability to devote a single studio to Vita development.
He doesn't strike me as being great at managing teams and I feel like a lot of the successes from SCE have come from outside his input.