I think Dusty is a nice guy, an ok regular season manager, and a bad playoff manager. Not Matt Williams bad, but bad nonetheless. Not bringing him (specifically) back is not a huge concern of mine, although he has probably done enough to get another job somewhere if he still wants one.
That said, you have to wonder about who's going to take a job where two division titles in two years gets you canned. At a minimum, anyone taking that job who has any alternatives would be (a) doing so only because this team has a lot of talent, something that may only be true for one more season and (b) is now likely to ask for a lot more money and/or a longer contract.