Not trying to stir the pot (I don't really care either way) but it should be noted.
Apple has gone backwards on battery life in their notebook line before.
If I remember correctly the 2010 MBA's had significantly better battery life than the 2011 MBAs (especially the 13") due to the Core 2 Duo to Sandy Bridge ( or Ivy bridge?) transition. Same thing happened with the 2010 13" MBPs vs the 2011 13" MBPs. And reviewers did note it but the sacrifices were ok because ultimately increased performance trumped the decrease in battery life. NOTE: Apple still quoted approximately the same time on their website but reviews that actually tested the different models noticed differences of hrs in battery life ~10hrs vs <7hrs real world usage for the 2010 vs 2011 13" MBA.
So IMHO (as someone who actually isn't all that enthusiastic about retina displays but loves my battery life) I think Apple will not have an issue with going backwards slightly in battery life in order to add retina screens to the MBA. Eventually the technology will catch up and they'll get the battery life back (Just as the 2013 MBAs finally surpassed the 2010 version while maintaining better performance) but if they come out with a redesigned MBA without a retina display no one will let them hear the end of it.
Now as to when this redesign is supposed to happen? I have no clue.
Apple has gone backwards on battery life in their notebook line before.
If I remember correctly the 2010 MBA's had significantly better battery life than the 2011 MBAs (especially the 13") due to the Core 2 Duo to Sandy Bridge ( or Ivy bridge?) transition. Same thing happened with the 2010 13" MBPs vs the 2011 13" MBPs. And reviewers did note it but the sacrifices were ok because ultimately increased performance trumped the decrease in battery life. NOTE: Apple still quoted approximately the same time on their website but reviews that actually tested the different models noticed differences of hrs in battery life ~10hrs vs <7hrs real world usage for the 2010 vs 2011 13" MBA.
So IMHO (as someone who actually isn't all that enthusiastic about retina displays but loves my battery life) I think Apple will not have an issue with going backwards slightly in battery life in order to add retina screens to the MBA. Eventually the technology will catch up and they'll get the battery life back (Just as the 2013 MBAs finally surpassed the 2010 version while maintaining better performance) but if they come out with a redesigned MBA without a retina display no one will let them hear the end of it.
Now as to when this redesign is supposed to happen? I have no clue.