I don't regard being in wildshaped form as equalling given enough time to prepare. once a druid has natrual spell why not be in animal form most of the time you're adventuring. I haven't seen a druid have several rounds to buff up. they seem quite potent without it.
Inability to talk to the party, for one.
That aside, BardStephenFox gave you several examples of other classes dishing out far more damage. Why don't you feel that those classes are overpowered?