I believe they claimed they were making development patterns more random to some degree. You can't build a formula to predict random changes.
But my sense so far is that the old formula will still be a fairly good predictor, even if it's less exact and consistent. It's more likely to be far off in one or two categories, but in terms of overall value for a player I don't see a big change. The formula was never exact anyway, given the effects of coaching, training, and playing time.