I think there's this phenomenon that occurs when a person starts medical school wanting to go into a field they're passionate about, something that is sort of on the less competitive side (like primary care), but then does better than maybe expected in classes, boards, and rotations during medical school. Then they realize there are doors open for them in more "lifestyle" specialties, specialties that they know they could grow to like and enjoy, but maybe not love....(but either way, the idea of a great lifestyle, money, prestige, etc is so hard to turn your back on). Ultimately, it ends up coming down to a "head" choice vs. a "heart" choice.
I came into medical school thinking I'd probably be an average med student. Fast forward to now, I guess I kind of sold myself short, because while I don't have the stats necessarily to do Derm (at least at a place I'd want to do it in), I did do considerably better than I thought I would over the course of the past 3 years. For a while this year, I seriously started to consider maybe doing Ophtho or Anesthesia. I had a tiny bit of exposure to both of these, thought they were cool, and I pretty much have liked all my rotations, so I figured I would enjoy these careers (I actually think I'd enjoy doing any number of things in medicine). But... I came into medical school originally thinking I wanted to do something general like Family Med, Int. Med or ER, and I ended up loving my Family Med rotation... and I can't deny that primary care is really a heart choice for me. I like variety, and I love close patient interactions, and I like the traditional role of a doctor, and while having a huge paycheck and great hours are obviously rewarding, being a primary care doc is something I think I'd get a lot of personal fulfillment from. And I can think of many ways that ophtho and anesthesia are very rewarding, and very important to patients' lives, but still something doesn't sit right with me about them. I think everything I've ever chosen to be involved with (in college and med school) and everything I've always found personally rewarding leads me to primary care.
Sorry to be longwinded, but basically, I can totally relate to the ego vs. the superego thing. I think you just need to figure out - how important is it to you that your job feeds your superego? We have to do this for the rest of our lives...I just made a decision that, even though some days will be hard, some days maybe I'll wish I had more money, and some patients will be annoying, when all is said and done, I really want to have a job that feeds my superego. It's something that's important to me, personally.
One more thing - this is just me, and this might come across as obnoxious, but I like the idea of being somewhat overqualified for the field I choose in the whole residency application/match process. I want to have a lot of options, and I'm sick of the constant over-achieving... I'll always try and do my best because that's my personality, but I'm ready for this constant pressure to ease up a bit... I don't really want to be in a field where everyone had to be super cutthroat to get there. To the OP - as much as your stats are amazing, I still don't necessarily think you'd be "overqualified" for derm (speaking purely in the sense of the match process)...there are just so few spots and most people who apply are just as amazing. I think you'd still have to do a lot of competing, and it's still gonna be super stressful. In ER, you'd have a ton of options...you could find a place you really love and feel confident that you'd get a spot. Just another thing to think about (i.e. how important is a stress-free 4th year to you).