Same, really do use the sling a lot and love that it's there when I'm hot.
Exterior vs. interior is a tough call. I prefer exterior personally, but when in Ldn for example I'm conscious that some drunkard might find it irresistible to yank, or it'll get snagged on something like a door handle Inspector Clousea style lol
Gravity pockets, I'm glad they exist but they don't get much use if any. I used to put an oyster card in there, but don't use one anymore.
TBH with all those features, escape zip, force lock etc, I can't say I use them much but I'm glad they are there, because they look cool to me and it's nice to have the option of use..
Be cool to see some new modern day features also, air pod specific mini pocket on chest / chest interior would be pretty sick