It's good to hear your observations & experience. The 3600 is beginning to look like a good solution for me as well.
LOL about that Denon terminology
. Denon's owner's manuals were probably written by Japanese engineers who knew little or no English. The Japanese I've worked with all were good scientists, but spoke & wrote English in a strange way. I don't know Japanese grammar, but they began a sentence with the middle of an idea, and then went out in both directions. I had to think/listen very hard just to understand them. Once written these manuals were shipped to someplace like Singapore for translation to English by guys who knew nothing about AVRs. In contrast, the Yamaha manuals I've seen were written in good English.
I'm pretty certain that my center and rear speakers can be driven by 105 watts. I had a much older Denon AVR that produced 70 wpc, and it drove those speakers fine.