My following comments are speculation, but: The card designs could have been approved around the same time period as the first wave of 1996 cards, the contract could have enforced the release date of 1997 to stagger product hitting the market, the contract could have stipulated mew was to be withheld until approved, or indefinitely, or permission triggered by some other event such as a sales target
While I guess you could try to flip it into a 3/4, and that might be the right line in some situations, I think there would be decks (at least in Standard) that would play the front side as a sorcery
If you have two non-Hydra creatures with Wildwood Scourge's ability (perhaps because they were mutated using the Ikoria: Lair of Behemoths mutate ability), putting a +1/+1 counter on any non-Hydra creature you control will cause the two abilities to trigger each other indefinitely
And with a catchphrase like Gotta Catch Em All., its easy to understand why
Card x10 Play Sheet x1 Additional information