Update - I just flew TK through SAW and they built a beautiful TK only lounge in the style of the IST lounge, but smaller. Nice bathrooms with showers, pide baker, salads, olive bar, pool table, TV lounge, luggage lockers, etc. but really uncrowded. Sadly, they did not have any desserts and they did not have the grilled meat, the cheese or pasta stations that they have at IST. (even the crappy priority pass lounge across the hall has cakes). That said, it's a huge improvement over the prior lounge if only because it's 3x the size with 1/4 of the pax.

Furthermore, for my international transfer inbound from MUC, I didn't have to go through security again at SAW which was always the worst part about transferring there. It was like a domestic EU or USA transfer right up the jetway and a few hundred meters down the hall to the lounge - really enjoyable experience overall. Now if they'd just get cakes and grilled meat then there's no reason for me to change in IST with all the chaos there.