Hall of Fame
Yeah, definitely looks like an amateur. Just no way those 80s or 90s guys could fully swing on a backhand. I mean, just watch this link: Edberg hitting backhands...I think groundstroke technique has definitely changed, and this is independent of strings. You mention children being taught to swing out. Look at some 90s matches on youtube. The one-hand-backhand players don't follow all the way through like we do now. They have this abbreviated follow-through that stops early and looks a bit awkward, a bit like an amateur player. I wonder if this is partly due to pre-2000s players still using such heavy racquets. I wouldn't be able to follow all the way through on backhand with my arm turning over at the end if my racquet weighed 400g.