Lots of good points brought up here. I first got into watches over a decade ago, and I was enamored with divers, especially Rolex divers, and Speedmasters were nice, but not really my thing. About 7 years ago, things clicked for me, mainly down to the Space program connection, and I bought what I thought was the perfect modern Speedmaster for me, a 3592.50 (I was also semi-hunting for a 145.012, but never really got serious with that quest, and I regret that greatly now). Well, I really didn't bond with that watch, and moved it on within a couple of years.
I came to realize that while the Speedmaster is an overall simple design, and while that's one of its greatest strengths, a few details make all the difference for me. I love the applied metal logo, stepped dials, and more than anything, the beveled/stepped subdials, all things the modern Speedmaster Professional no longer has. I also realized that while I like tritium patina in general, I don't love the way most tritium Speedmaster dials and hands age (although I would be more than fine with a 105.012, 145.012, 105.003, etc. on my wrist).
So for me, the modern Speedmaster Professinal is kind of boring (although still very cool). I crave a little extra in my Speedmasters, and now have three modern Speedmasters which I adore (but none are the standard Speedmaster Professional).