First of all, since your topic deals with datamine stuff, you might want to put that in a disclaimer in the topic title or something, lest you be murdered in your sleep.
CYL Ike isn't entirely terrible. With his unique A-skill, Steady Breath, he gets Def +4 when attacked AND Heavy Blade (on top of Urvan's Special charge -1). This puts him at 39 Def at neutral when defending, and Aether is charging crazy fast. His biggest problem is that he might want to drop Beorc's Blessing for Quick Riposte, since leaving enemies alive kinda sucks.
With Aether, if Ike gets doubled (which will happen a lot) and he has Quick Riposte, the first hit from an enemy reduces the Special counter from 4 to 3, then Ike's counterattack takes it down to 1. After his opponent's second hit, Aether will be charged, and his second QR hit will be quite painful. This works with Ignis too, and his Ignis does 31 damage.
But if you don't want to drop Beorc's Blessing for QR, you can change the Special to Bonfire, and put Quickened Pulse on him for the instant 19 damage Bonfire.