I think perhaps from a writer perspective they wanted to keep the return of Dizzy until this far into the story because it helps build the climax, but it doesn't leave a lot of time for sentimentality. That is, unless you were to have Ky foreshadow it some. Perhaps he could think on the last time the valentine showed up and how Dizzy was nearly killed with the rest of the gears, then we would be able to see his plight and concern. Perhaps he would even miss her and dwell a bit on her sealing, wondering when the seal would release or if it would be safe to let her free. That would foreshadow her return, show us that Ky does in fact care for and love his wife, and give us more reason to care about their relationship. Instead, this scene comes up and this is the one moment we have to take it all in."
This is why I said you missed the point because 90% of those posts are from Overture Short Stories, Overture game, and Vastede XT. Especially when Ky desperately tried to find a way to turn her back w/o killing her. He prevented her death from the rest of the Gear in Illyria. In Vastede, which set time during XRD story. The fact you felt forced because you spent so little time with them in Xrd story. You didn't see the progress they made from Ky, Dizzy and Sin perspective at all. Your argument was that it came out of no where. I said was natural because it was building up from the previous game. Sin gave a shit to Ky since at the end of Overture when he actually cared for Ky at the end of Overture but still reluctant to call him father. The possibilities you mentioned was from the previous games that you skipped. Did you pay attention that I ALWAYS say Xrd story is a DIRECT SEQUEL to Overture that you skipped? Your enjoyment was already penalized because you didn't understand the true nature of a Valentine, Sin relationship with Ky from the past game and how Sol acted with Elphelt so differently. The fact that the story showed the flashback with Aria gave you enough hints that Sol actually cared about her made sense.
I said it again, your possibilities were already present in the previous games. This scene was the conclusion of those possibilities.