Something I do want to test (if I make yet another alt sometime) is what dialogue you get for starting the Crystal Tower questline but leaving it half-finished! Not just for this, but for Nero's first MSQ reappearance - proposing the use of Omega in pre-Stormblood - Cid has different remarks depending on your CT progression. So I can watch the scene with it fully done or fully not-done, but what I do want to see is Cid's reaction if you left WoD uncleared and Nero stuck in the rift!
Shadowbringers could be similarly interesting since...
At that point you're going to recognise G'raha but not understand how he ended up in control of the Tower or know that he got sealed inside it. So the option to call his name might exist, but ending dialogue would be different.