As I said in my post, replace Grilli for part of the year. And yes, the bullpen should be improved, but it's highly unlikely we get Withrow, Paco, and Shae back and they all pitch like gangbusters and are strong right off the bat. They are all coming off major injury, and will likely struggle for a while till they get back in the groove. So while I expect it to be better than this year, it's highly unlikely to be a major force in 2016. In 2017, sure I could see it being a major strength, but we are counting on way too many arms coming off injury for it to be great in 2016.
And even if Julio returns to his prime form somehow in one offseason, we still would just be equal to what we had this year with Wood on board. And the rest of pitchers are very young, even very good starters generally struggle a bit their first year and a half in the league, so I doubt Wisler and company blow the doors off next year.
Unless we sign a very good #2 starter or better in FA this offseason and have Julio return to his 2013-14 form we are unlikely to have a pitching staff tremendously better than this year. If we don't spend money on a good SP this offseason (and this last trade with Bourn and Swisher makes it unlikely we will have the money to spend this offseason for one), and Julio doesn't get way better, then there is a chance our pitching could actually be worse next year.