Seems strong on paper, but I think it might be way too expensive. You definitely need to be ahead on board to get value from it, hit atleast 3 minions. And it is just not as flexible as Mark of the Lotus, because of 3 mana, you might just fall behind and get nothing of it. A very "win more" card.
I think the cost of 3 is because it's a twin spell. If it cost 2, you could get +2/+2 to your board for only 4 mana, which is too strong. The old druid epic that cost 7 used to be +2/+2, so it's a slight discount compared to that, plus with Violet teacher, it makes 2 tokens. Overall, another good boost to token druid I think.
This is pretty much garbage tempo. Compare to Branching Paths for example, 2 more mana and you don't have the additional room for choice. It's extraordinarily overcosted.
On the other hand, Token Druid will use it anyway as it wants the effect no matter how overpriced it might be.
Like someone else said, this might have costed 2 mana and Blizz nerfed it to 3 mana during playtesting. It's still a great card because it's twinspell so you can use it twice. It's a permanent 1/1 buff unlike savage roar which is usually only played when you have lethal or you must trade up just to survive.