I like Lucacc's idea.
My issue with the druid is not so much the flavor. I just think that morphing into any animal at any time is too potent for a level 1 character. The ability to transmogrify into a mosquito is not far from the ability to teleport. Mundane barriers like castle walls, prison cells, and pit-falls become useless. Gotta get that idol, but you're afraid the floor is rigged? Just send in pigeon man.
Rather than being a nature-loving, free spirit of the forest, the druid in my campaign has become the thief, assassin, and spy. Got a campaign based on political intrigue? No problem. The druid just takes the form of a house fly and finds the bedroom of the local baron. The druid morphs back to human and slits the man's throat. Alternately, he becomes the literal "fly on a wall" and listens to all the plotting and planning.
For every physical barrier in the game, the druid has an animal form to solve it. So my players start every encounter by sending in the druid. The rest are just along for the ride.
Are there creative ways to curb this behavior? Absolutely. But then the game devolves into GM vs druid. Can I just ask the player not to be so opportunistic? Sure, but if I have to go to those lengths, it suggests to me something is a little broken.