Has it though? We had the same last season and the thought was that it took a season for the players to adapt to the methods, and yet here we are again, there was also the notion that once players came back we would improve, we didn't, we got worse.
There's nothing concrete to make you believe we won't be in the same boat next year, we're actually on a downward trend and so logically there's more reason to believe that we will be worse still.
If, gigantic if, he stays, then there needs to be major upheaval in terms of back room staff. He absolutely must either bring in, or have brought in for him, a top tier coaching staff that can enact all of the nice fluffy ideas he has about "attacking" football.