Wow...it is actually nice that W responded with a thoughtful message which does not require an immediate response although I'd shoot off a brief note acknowledging it.
How about:
Wanted to touch base briefly to let you know that I got this message and I'll get back to you on this a bit later as you have raised a question that requires a thoughtful response. Have a good day.
Honestly, I am going to need to chew on W's email some more to get to the real crux of it. She sure surprised tall of us here. Right off bat, I sense that she's fearful of going back to the same broken M and she's not seeing how it could be better from where she currently sits from her perch. She's trying to see how the future could be brighter and more optimistic.
