The designers obviously asked themselves what makes women look powerful, and couldn't think of any women more badass than Melanie Griffith and Sigourney Weaver in Working Girl. But seriously, Season 7 was so '80s that I was fully expecting to see an Oingo Boingo poster over Daenerys' bed when she was having sex with her nephew. Season 7 was so '80s that I know how they traveled around so quickly: Jon Snow has a DeLorean. Season 7 was so '80s that I'm fully expecting Cersei to name her baby Reaganomics. OK, I'm done. For now.
The point isn't only that there were shoulder pads; the point is that shoulder pads were suddenly everywhere. In a series that's supposed to take place over great distances, and which started out with vastly different costuming to display regional tastes, it's slowly become more and more homogenized, and it's now obvious that one person is dressing everyone. And that one person fucking loves shoulder pads.