Before entering a polyamorous relationship I was married monogamously for sixteen years. Although I am not personaly polyamorous, the communication between my girlfriend, her husband and me is second to none!
More attentive? I would say definitely yes because the need to communicate requires more attention which promotes deep closeness. The likes of which I have never felt. There is also struggle there for sure.LOL! But all relationships have that.
I will agree with you about "open relationships". To me it is the depth of polyamorous connections that set them apart. I would not want to be in an open relationship but will work to flourish within a poly one. I respect the caring and have little appreciation for recreactional sex..although I thought that would be my nature...strange how you learn things about yourself.