I don't agree sorry, is a bad dicision.
Take a look
Check the difference between both. If you count it, Kanto 2 has 50 pokemons, Johto 2 has 24.
The chance to get Larvitar from a box would be big and it may affect a bit our economy, cuz Larvitar hasn't a big price already. And yea, I know Johto box 2 has a low price too, but still, it would be too much easy to get a good pokemon.