I think it's great that you're already thinking of the next DO, and that you're asking for input.
I'm also a little glad, although it was fun, that you aren't going to be the FA's because sitting in Row 1 meant that my seatmate and I missed out on food and drinks that somehow had always run out before it got to us. Worse for him than me, because I was in the aisle seat and had a great view when the cockpit door was open for the TLS flyby; and it was fun it help out with the safety briefings by handing up the next item to be displayed and explained, especially the oxygen mask.
I'd go for a weekday run with weekend bookends, but won't know my schedule until much closer to the actual time for it. Much more so this year than last. Cost would depend on what's going on.
I like the Istanbul idea (was last there in '74) and also Cuba (have never been), the latter on the way down to see Embraer? Stop in Panama for Copa on the way back and visit the Canal, from a time of a different form of travel? Or, if RTW, Panama Canal & Suez Canal, though I'm not sure about *A aspects of that. And the last idea I have if you set it up for Brazil - a side trip to Iguazu Falls.
Definitely would love to have that Condor gang along with us.
Looking forward to reading up as you go forward.
Thanks again.