Lol you realize if they banned forest instead of shiftry forest would have never seen a day of legality
It shouldn't have been printed, so it would have been better for it to not have a day of legality. TPCI had to choose which card to ban to get rid of Shiftry Donk and they chose the 'least restrictive' option like they did when they banned Archeops. They found that was a mistake when FOGP produced another deck with a disproportionately high chance to win the game if it wins the coinflip with Deciduplume. This wasn't going to stop happening, and was going to get even more dangerous with Archeops banned since you wouldn't have to deal with the counterlock.
I mean if they didn't ban it now, they'd have to take it into account when designing any grass evolution from here on out or risk breaking expanded every time they introduced a good new grass stage 2.