Yes, and your cables, especially interconnects, also helped with the tonal balance. My Monster cables were too warm, the ZenWave Audio D4 interconnects seem neutral and very extended, as also judged from hearing them in Madfloyd's system. This system also reveals just how stunningly resolving your D4 cables are.
That is a possibility, but I am always worried about loss of dynamics from the crossover. With a high-power amp this will be less of a problem, but do I want to really try it? Not sure. I love that my REL subwoofer runs in parallel with the main speakers, without crossover from them.
But also this needs to be done extremely well. For my previous speakers, the Ensemble Reference monitors, there was once an offering just like that, called the Ensemble Profundo. Yet at the dealership where they were in love with the Ensemble monitors they were distinctly underwhelmed by the result. Also here they were complaining about loss of liveliness by the crossover. In addition, speaker stands with a woofer are rather likely to affect the soundstaging, endangering the 'disappearing act' that monitors are so good at -- not that larger speakers cannot completely disappear from the soundstage, it is just more difficult for them to do so.
Every speaker design is a compromise (just like every speaker placement in a room!). I like the monitor/sub compromise best, but again this is a personal preference. I can easily see the merits of other approaches, as I have indicated on the previous thread page. These will be best for other tastes. The beauty of this hobby is that there are so many approaches to great sound, something for each of all our individual tastes. And tastes vary also among those who have the same reference, unamplified live music. After all, we all experience the same thing differently, through the prism of our individual personalities.