What do you guys think legacy servers might look like?

Let's assume that they do happen, and that blizzard doesn't completely fuck it up and actually makes something good.
Do you guys think it would start with patch 1.0 and work it's way through patches, talents and stuff? Or do you think they would start with 1.12 talents and spells like pservers start now, while progressing content like they did a decade ago?
Basically, do you think the legacy servers would run and progress just like vanilla did back then, or will they take a somewhat different, more pserver-like approach?
Do you guys think it would start with patch 1.0 and work it's way through patches, talents and stuff? Or do you think they would start with 1.12 talents and spells like pservers start now, while progressing content like they did a decade ago?
Basically, do you think the legacy servers would run and progress just like vanilla did back then, or will they take a somewhat different, more pserver-like approach?