I think it's possible that de Blasio underperforms but I can see, anecdotally, that the Mayor's race is not as sleepy as it is portrayed in the news. There is heavy campaigning from de Blasio, Malliotakis, Dietl etc. camps and there are also key County Executive, etc. races in Nassau, Westchester, etc. Making it more interesting, the Constitutional Convention ballot proposal means that unions, etc. are mobilizing voters as well.
Its still extremely unlikely De Blasio loses. Polls have shown him with 60 percent of the vote. Are there any city council races republicans could gain?