Thought I'd weigh in on the ongoing Newcomer debate, since well yknow...
1. I feel as if getting the vintage rolex would be a waste. Why? Because you already have the speedy pro. And a vintage sub would be kinda redundant. That's not to say that you shouldn't get it at some point, but swapping out the MC for another sports watch at this point in time doesnt make sense.
2. The MUT Moon is amazing, if cold. As you know, I was kinda "over it" for awhile. I think that stems from the fact that it can be a pain to reset the date/moonphase. So my piece of advice is to get a winder, and a hell yes to the other straps.
3. Try the GO on. This is a must. I may be in the minority on this one, but I prefer the GO to the Lange (and dont see them as related watches either), but like you said I wish there was a merger of previous case/bezel size, and the dial of the contemporary one. If I could choose one Lange itd be the worldtimer, BUT if I chose a worldtimer itd be the PP not the Lange.
4. Tangential but related. I love the IWC portofino moonphase but alas its just too big for my wrists.