OR it can be used as a metaphor to explain things and processes the theory didn't address directly.. OR as a base for conversation about unknown matters..
But when it comes to actually choosing between two normative models - policies - that purport to give the same results, it is less useful. There the policy will either produce the desired results or it will not, and it's too late by then, and a mistaken interpretation of Ockham, to state that a simpler set of constituent parts in the model will more likely attain the desired result.
By then all you can state is that if it is observed not to produce those results then the model that purports to be normative has failed and is merely descriptive. (That happened, IMHO, with Marxism, but that's another entire and very large discussion). And yes, that's hindsight.
But to turn the circle, I happen to agree with you that Ockham's Razor can be very useful to navigate a choice between descriptive models where there are a large number of unknowns. That is absolutely what it's for.
I just re-read this. Does it make any sense at all? I think I'm going to bed... ;-)