More often than not, bad teams lose badly and good teams don't even let the outcome come into question. When all things are equal, and the scores are close, the outcome becomes closer to 50/50 and little things can influence it, including but not limited to the refs. When you lose or win a lot of close games, it basically just means you're mediocre because you're relying more on chance to win than anything else.
And because it's expected of me, that's why I'm expecting a bit of a resurgance next year from the Cowboys. Without Romo they were close in more than half their losses and in 2014 they basically won by over a TD in 2/3s of their wins. They allowed less to chance. If you figure your franchise QB is worth at least an extra TD a game, then they lost enough close games to turn that 4-12 record into 10-6.