I know what you mean. In most ares of life I am a huge advocate of simplicity, but when it comes to choosing a specialty I just can't reconcile. I have the sneaking suspicion that choosing a less competitive specialty may simplify med school and the match at the expense of complicating the rest of my career--probably by making me neurotic with the "what ifs" or "if onlys."
Also, MCAT guy, you are right on with the bolded portion. The frequently propagated advice "Wait until your clinical rotations to decide on a specialty" is total BS if you end up wanting to match into Ortho, ENT, Plastics, RadOnc, or Derm. It can be done but it's just not a great idea.
People interested in those specialties should start investigating them first year to decide if they want to jump through all of the hoops. When has it ever been a bad idea to start a project early? Obviously you want to "keep an open mind," whatever that means

but it's not like building an application for Ortho will hurt your chances of matching into family med if you decide to do so after 3rd year rotations.
However, if you think you want to do FM, and after third year you decide you want to do Ortho, you may have already effed yourself with a mediocre board score. If not you've got less than 1 year to network with attendings and try to work on some specialty-specific research. Talk about stress and a lack of simplicity.