It was a thing. Pre nerfs he was an absolute menace and I will say it says a lot about Tracers power that she couldn’t be dethroned by him despite him being so overpowered 
He suddenly becomes much more consistent when he does get into close-mid range and his ability to clean up kills with mines mid fight is suddenly a thing. It would have made a big difference.
Think how lowering his mine damage to 100, with the combo still being possible, sent his viability so far through the ground that they partially reverted it. Now imagine it in reverse with decreasing the fall off. It’s a big deal because it gives significantly more margin for error with his combo. If the minimum fall off damage isn’t as low, the fall off is less harsh so it’s more likely he reaches the 200 damage required with a combo. Consistency, not range, has always been Junks biggest problem in high elo.