I Agree...coming from someone new to DC comics, I never knew that Super Girl and Power Girl was the same character(recently learned this fact). My only real knowledge of the Power Girl character was the Justice League episode where she was introduced as a Clone?
all that to say- NRS making Power Girl look like an actual older version of Super girl is wonderful. Nice take IMO.
Galatea was loosely based on Power Girl, PG comes from a different Earth/Universe that was destroyed and she was the only survivor. Just like the Earth-2 comics are the same characters yet different PG is just SG but different.