Personally, I have recently decided that I need a very small collection. I have 3 luxury watches and a Seiko diver I use for the gym and occasions when I need a beater watch. I used to use a 214270 for that, but I sold it because it just wasn't 'me'. I also have a sistem51 because I find it interesting. I actually think that anymore than this will be too much, I want to wear my watches often and without hassle. If I can rotate enough that they're all wound then this is ideal. I think my MkXII will go in favour of the new big pilot. Then I'll basically be done, unless I get a serious dress watch for special occasions.
Also, I love your core Rolex collection. The Explorer II and the Milgauss particularly make my heart sing! And I'm not a Rolex guy. I think you made a great choice, I like to meet others in the 'less is more' club.