Why would it be one turn late? Sure you need to activate the monk before your mage, but it will still be same turn as a flower / crystal. Right?
Six of one, half dozen of the other. It would have to wait until the next turn to activate, while the Mana Flower gives you mana during Channeling, which is technically earlier that turn. Edit: This is relevant if you wanted to use your Deployment or First Quick Cast phase and needed that one mana, but otherwise it's effectively the same.
Come to think of it, it's actually probably pretty beneficial for a slow build Priestess to drop a flower and a monk in her starting zone, it nets the same channeling as two flowers, but is easier to defend since the monk isn't zone exclusive, plus he can defend himself and the flower if he has to.
Good job, Arcane Wonders. Now that I think about it, it's a nice card.