The determinist would point out that that is merely a practical problem, not a philosophical one. The free willist may point out that, without free will, morality has no meaning. If we are as determined as falling bricks, then Adolph Hitler could no more be blamed for his evil actions than Mother Teresa could be praised for her good ones. Simple, says the determinist. We will have to live without morality.
Many people are already moral relativists, or even moral nihilists.
Another argument a free willist can make is that we have this unique ability to stop and think about a decision-making situation. We pause before the high-calorie meal to consider the advisability of diving in. And we can postpone the decision as long as we like. Even if the actual choice we make at some particular moment in time is determined, the length of time we wait for that moment to arrive is not. Jean-Paul Sartre came up with an interesting free will argument.