Yeah it can be retconned like that but based on the whole plot at the time, I suspect Dr Lester wanted to be a Starfleet captain and thought the only way was to body swap with her ex.This isn't necessarily a contradiction. Lester's line "Your world of starship captains does not admit women." may not have been intended to mean "Starfleet doesn't allow women starship captains," but rather that Kirk's world as a starship captain didn't include her, since they were talking about their relationship not Starfleet.
The last line 'her life could have been as complete as any woman'...what the hell is that supposed to mean?