after training for a really really long time, I found a very good technique that has helped me connect with izunas.
Normally when I wanted to izuna, I would wiggle the stick and then swoop in at a high velocity, intending to “crash” into the opponent. When Vega uses his EX FBA and does the double strike, when his hands initially skewer into the opponent for the first hit, that is the hitbox you need to connect with when hoping to Izuna. While you can slam into people and grab them by coming at them very quickly, I found a method that is much easier and reliable.
Instead of steering at all after wall diving, don’t. Notice how no matter where you jump off the wall from, you will come and land a close distance beside your opponent. Even if they are full screen, you will be “magnetized” to them and will sort of gravitate in their direction. With this in mind, try after jumping from the wall letting yourself lob at the opponent like a grenade. Then, as you’re beginning to descend from your arc, try to line yourself up with your opponents shoulders, directly above their head. The way you want to time this is so that after you line yourself above their head, you don’t have time to steer, and hence, lose the perfect trajectory you have gained. If you steer in unintentional directions its because your initial steer is to early. All you have to do is the barcelona, don’t hold any directions, then as you come nearer your opponent just hold right and press punch when you think Vega can grab the opponents shoulders / head. Of course this differs with every character: but this method makes it easier for everybody.
After steering my barcelonas for so long, I now think that letting Vega glide towards them, then making sudden movements is much better. You can still cross behind someones head and surprise them because Vega’s velocity in the air is sort of exponential: you can easily make it look like you’re whiffing, or hitting their front, then veer at top speed for an izuna or cross up. I highly suggest you try letting Vega steer himself in training. Makes it a hell of a lot easier.
Note: Also, EX ST has greater range than a standing roundhouse. Less than the forward and fierce, but greater than crouching strong and roundhouse. RH ST is shorter than crouching strong but longer range than the close pokes, like a crouching medium.