Will BA/QR be? In recent weeks BA has been flying 1x or 0x to IST, often cancelling its lone flight and just FIM'ing people. They are now down to one full time employee at the airport, and speaking of lounges, they closed theirs years ago, so although I would hope that they will have a lounge or that there is some sort of 1World lounge, I am not holding my breath. QR may increase services, but what will they possibly ever do, 4x to Doha, one day? I am happy to hear taht Skyteam is giving it another go at the new airport since they abandoned their current IST lounge last year, and I can dream that this might mean a comeback for Skyteam carriers in Istanbul, because currently, you are looking at 1xAF (Joon, but will be AF again in 6 weeks), 1x KL, 1x Tarom, .5x Korean, 1-2x MEA, and 3-5 each SV to various destinations and 2 x Aeroflot. Five years ago, it was up to as many as 5xAF (4x to CDG and 1x to Toulouse), 3xKLM, 1x DL, 2x Tarom, 1x KE, 1x CZ, 2x MEA, 5x SV, 3x Aeroflot. So Currently 9-10 flights per day, when before it was above 22 flights per day.
The rumor is that as some point after the new airport really opens AF/KL will raise frequencies to 2 and 2, but we'll see.