The finale was beautiful. After three seasons, I was so happy to see Josh and Lucy get married. Josh more than earned his happy ending.
Simon Rich has been saying in several interviews that they'll do more episodes if they get renewed, but I'd be fine if this is the series finale. I don't want this show dragging on too long, and I don't think a season about their marital problems or trying to have a baby would be that interesting.
Also, I just realized the actor who plays Tom (Mark McKinney) also plays Glenn on Superstore.
They let him do both shows.