The way I see it, the only use of being able to predict the future is being able to prepare for what it going to happen. After all, if we predict something to happen but don't accordingly make any adjustments until that something happens, what was the use in correctly predicting that something would happen? Sure, we can claim bragging rights or think about the novelty of it, but what is the use in that?

There's no way to predict whether a given dream is going to predict the future or not, so to reliably make use of all of the predictions dreams may make, we have to assume every dream is making a prediction of the future and make adjustments to the future according to what we think is the prediction of the dream. If we assume a prediction won't manifest itself, it really isn't much use as a prediction. If we take the predictive power of only 50% of the dreams seriously, the other 50% may just as well make some or all of predictions that came true that we didn't take seriously.

That said, if I were to attempt to tap into the possible predictive power of a dream, after being lucid, I would simply ask a dc or the voice-over of the dream to tell or show me what is going to happen in the future.