Anyone expecting a perfect record is obviously going to be disappointed. Searage overhauled Happ's delivery, hence how a 32 year-old Happ with his 5th team was able to turn such a corner. Happ spent parts of 3 seasons with Toronto before returning there, and the pre-Searage numbers are putrid compared to the post-Searage numbers.
The thing with Nova is that I'm less inclined to give all of the credit to Searage, namely because Nova has walked 2 batters since becoming a Pirate. That's Kershaw-esque, and not sustainable at all. This one could be more of a change of scenery breakout than a ton of meddling working out. That said, Nova has been a far better pitcher his last 4 starts than he was his first 3 in Pittsburgh, so I don't think it's fair to write off Searage entirely...but I can easily buy this being little more than a hot streak. Unfortunately there's really nothing he can do this season to ease my concerns, since they're all based on how he'll fare on a larger sample size with more pressure put on him.
But yeah, going forward with the strategy of 'the pitching coach can fix anyone' is just inviting disaster, and that played out this year. Liriano refused to change, and a pitching coach can't help those who refuse help (doubly infuriating when Searage already fixed Liriano once, but the batters adapted). Nicasio has been the definition of a mediocrity, Niese was an unmitigated disaster, etc. I just don't think that was the Pirates intention heading into last season, Huntington just seemed to be blind-sided by how absurd the market for starters was. He can't afford to stay on the sidelines again this time around.