I still not very good at using the jump-over and back B. Do you guys think it can be an effective move in the actual combat?
Easily. In other KoF's, Iori's high-speed pressure of hop CDs and quick command crossups are very irksome. The hitstun for the move also feels longer than normal, and pulls you towards him, leading to even MORE pressure if blocked, or just solid combos if he hits with it.
Since it's got such a long reach backwards, it's a very nice tool. For example, lets say Maxima does a Vapor Cannon before your hop, moving him away from you, as he steps forward. While most crossovers would miss, and give him more time to recover, Iori will possibly tag with a meaty hit, and pull him in close with this hit.
He has a great set of normals and specials overall, and a neomax that can be used as an anti-air aganist sloppy jumpers. Along with his safe specials leaving him in-your-face, make his whole arsenal very dangerous.
Edit: At the 12 min point in this vid, you can see a match where Iori uses his jumping crossup kick very well (Though it's in KoF 98!). Similiar tactics work in XIII as well though, so use this as a base guide of how the move can be used effectively.