I don't know about that. Parker and/or Kirby must not like it, or they would have simply said, "It's new, it's being implemented, it's what we're going with."

Maybe they think the design is too expensive to implement across the fleet? (a la Delta's change a few years back)

They're not the type to change it just to have their 'mark' on the new airline. And certainly not if it costs a lot of money. So there must be something behind the current, "It's under review," stance.