Wouldn't say 2015 was the end of AA's window. The core was still very good and made it to the ALCS again in 2016. Both teams had great chances at making the World Series, two years in a row. But yeah sucks they came up short against the Royals and Cleveland those years. As for 2017, who knows if AA was still around what other moves he would have made during the offseason.
AA decided to go all in starting in 2013, which backfired and the team was somewhat decent (83-79) in 2014, but not good enough. Donaldson + Martin the following offseason really helped, but the additions at the trade deadline really pushed the Jays over the final two months and into the Postseason.