I'd rather wait for some proper research. Most of these sorts of documentaries are painfully slow, weak on content, and strong on sentimentality. It might raised awareness but to who? Your average football fan won't give a shit, and the powers that be have too much money to lose so they'll quash hearsay and discredit medical opinion. The only way to break the status quo is more research. Balls are lighter already.
I think that was the conclusion of the documentary too. And it was good to see that independent research is being conducted into this, regardless of football authorities' reluctance to fund it.
(Also fun fact from the documentary, balls are not lighter at all. They are more waterproof, so they don't get soggy and heavy when wet, but in the dry they're about the same weight.)