Perhaps most disappointing, had a fourth season been ordered, would have been Charmaine (Rosemarie DeWitt) and Neil's (Patton Oswalt) move to Houston. They are enjoyable supporting players, and while they may need distance from Tara and her drama for a happy ending, including an upcoming (finally!) marriage, they would have been sorely missed. Of course, now I guess they don't have to be, because the whole series will be missed. Had the series been picked up for another season, they may have moved back or taken frequent trips back and forth to keep them involved in the story. Guess that decision will never have to be faced.
Max gets some serious development right at the end. Being married to a woman like Tara must be a serious struggle for any man, but much of what Max goes through has been kept hidden. Marshall forces some hidden disappointments to the surface with his film. Even though Max doesn't like it, much of what Marshall says rings true. Max's pain could be because his son hits too close to home. Max's dinnertime eruption in the series finale is a fine way to show how he is not as easy going as he often appears to be, and is struggling to hold it together. Further exploration of his psyche, and why he does what he does, would be welcome. If there were more episodes, which there will not be.
Marshall also gets some intriguing growth in season three, as the death of Lionel (Michael J. Willett) spurs him to also release pent up emotions. Faced with serious loss, Marshall gets a renewed sense of today, which could be construed as a commonly used device, but in the hands of Willett, opens up whole new areas of the character. Marshall is the steady rock of the household, and his losing it helps Tara and Max see how their lives affect their children. It's a revelation that is obvious in retrospect, and worth talking about. Marshall needing some distance makes sense, and it a logical, good storytelling move. He will be available to love and help them, but he is not a care taker, and he should not be, as Max and Tara agree.