Perhaps I should have clarified, I spent the day in Atlanta, and didn't return right away. The inaugural arrived at and departed from F14. The inaugural had a 2.5 hour turn. I have a feeling that this was so that they had the big open space in the middle of the concourse for the opening ceremony, and so that it's a nice appealing looking terminal to portray on the local news media. The other flights of the day all used D3. F14 looked like a sleek modern facility. D3 looked.... well, it wasn't quite as bad as LaGuardia... but LaGuardia at least has more seating at the gate area. D3 is right across from the Spirit gates.
As far as JetBlue building anything (signage, custom gate monitors, etc), it doesn't look like they've actually built anything at F14 or D3.
I posted a
Trip Report over on the Trip Reports forum for those who are interested.