Rachel, I'm pleased you shared the experience of the new terminal, where Splendor was berthed last November too. It is indeed a stiff walk to reach the exit and our pleas to take the shortcut to avoid the Duty Free shop (there was an open door which would have cut the walk by half) were denied on every occasion 😒 But we, too, had a great tour whilst in the city and felt really happy that the excursions cater so well for those of us who are already familiar with Istanbul. I will note the evening tour for "next time"!!
(Our recommendation is the Go Local tour of Beyoglu and Moda, btw)