Great question!
I would definitely agree that there is a perception that Old Valyria was the height of human civilization, which gives people in Essos a sense of cultural superiority, similar to how Renaissance Italians lionized classical Greece and Rome. After all, at the same time that Cosimo de Medici was ruling Florence, the English were still fighting the Wars of the Roses…hence why the Renaissance is more of a place than a time.
As to how perceptions have changed over time, I think it’s hard to say, especially since the WOIAF didn’t give us much information about pre-Targaryen Westeros/Essos relations.