1. I've commented on this before, but I'd like to attack it from a new angle. A common plank in the freewill defense is appeal to natural law. In order to make morally responsible decisions, our choices must have predictable consequences. That requires the uniformity of nature. Hence, God can't intervene too often without having disruptive effects.
2. I think there's a grain of truth to this theodicy. And it's hardly exclusive to freewill theism. Popular caricatures notwithstanding, Calvinism isn't fatalism. In Calvinism, it's not merely the outcome, but every step leading up to the outcome that's predestined. Hence, breakfast won't cook itself whether or not you get out of bed.
3. An elementary problem with the freewill theist appeal is that life is often unpredictable. Much of the time we're flying blind. We can't reliably anticipate the end-results of our actions. It's just a guessing game. And even when the consequences are foreseeable, there's a big difference between having a purely intellectual grasp of the consequences, and having to actually experience the consequences.
Many people, including many Christians, if they only had the benefit of hindsight, would avoid making some of the decisions they did. And that isn't merely regret over impulsive decisions. You can make a thoughtful, conscientious decision, with the best available information at the time, only to have that blow up in your face. You can make a reasonable, responsible decision, then helplessly watch it turn out for the worst.
4. According to freewill theism, moreover, a large part of what makes the future so unpredictable is the libertarian freedom of human agents. And the further into the future you project, the harder it is to extrapolate from present trends.
It's like a game of chess. Good players think ahead, several moves deep. But each subsequent move in that calculation is exponentially more complex than the previous move, because each subsequent move is contingent on which of all the possible moves opened up by the previous move the player will opt for. Each player's next move must consider multiple chains or nested outcomes of hypothetical moves and countermoves, branching into infinity.
Nothing could be more destabilizing to predictable consequences than the wave interference generated by so many competing agents. So many countervailing choices by other agents, which neutralize your singular choice.
5. It might be objected that my argument commits a category mistake, inasmuch as the uniformity of nature is categorically different from the libertarian ability of human agents.
But in a couple of respects, that's an arbitrary place to draw the line:
i) If predictable consequences are a necessary condition of praiseworthy or blameworthy choices, then it's ad hoc to insist on the uniformity of nature, while allowing human freedom to run riot. For that undermines the principle at least as much as heightened divine intervention.
ii) Furthermore, the dichotomy isn't nearly that cut-and-dried. Human agents manipulate natural processes to produce outcomes that would not occur if they let nature run its course. Examples are endless. Consider just one: the sarin gas attack in the Tokyo subway. In one sense, that exploited the laws of nature to produce a chemical weapon. However, that combined natural elements in unnatural ways.
In sum, the freewill defense appeals to two divergent principles. They tug in opposing directions.