Agreed with the OP comment. The continuous Frog production warrants a shift upward in cost somewhere, either a small shift in the chain of activation costs or a large shift in the initial casting cost. See: FFQ, Pharaoh, Graveyard.
The initial cost needs to jump to around 6-7 or one (possibly both) activation costs need to be raised by 1 point so that this card doesn't entirely pay for itself.