I would suggest finding a new pdoc. Maybe asking your MD for recommendations. I don't think that your MD is just going to let you dictate all your medications and changes. It's one thing for a doctor to listen to you and for you to advocate for yourself and another for a doctor to just write prescriptions because that's what you want. I'm sure there are ethical guidelines prohibiting that and there are probably legal ones as well.

My pdoc listens to me and gives me options/choices but he's conservative when it comes to changing and adding medicine. He'll only change one medication at a time or a dosage at a time. Taking your example, if I was taking lexapro and my pdoc wanted me on 50 mgs, but felt it was better to only increase by 10 mg, then we'd increase by 10 mgs until I got to 50 mgs, then wait and see what my reaction was before adding or changing anything else. Because if you start changing multiple medications and stuff happens (bad reaction or good reaction) you can't tell what it's from.