true, but you have to take in consideration that zekken started as second duelista/flex since he joined, Asuna has always been the Duelist and maybe he just lacks that intelligence or whatever to flex.
Also, if asuna start flexing, Ethan would have to play either Sentinel or controller and changing roles that much was the reason not to get Cryo:
But i think Asuna/Ethan duo is cracked, but ethan needs to flex more agents, not Skye and Sage only.