Visual approaches containing steep turns? Now there's an interesting concept. Fun, Fun! (extracting tongue from cheek....)
I must admit to never having looked through them, except to see the horizon approaching the top of the loop. (Ah! tongue still in cheek....) The B707 only did a barrel roll I remember.
Astro Nav? & where did the Nav sit? Ah, that's what they meant by the 'observers's seat'. Didn't the B737 come after the B727? and was it really contemplated that these a/c, with no nav, would fly in areas requiring astro? I admit, all before my time; just curious.
However, can't remember ever looking through them doing visuals, even tight ones. Usually impossible, anyway, because someone, before tailored sun screens arrived, had stuffed maps or newspapers to block out the sun.
A sun roof would have been useful on some RH circle patterns from the LHS in B767's, though.