Is Nina a better dancer than Azura in anyway?

Having more dance/singer units is welcome in things like Arena Assault, but it's hard to say if one is better than the other.

Azura has better attack, good speed, crap defense and okay resistance. Ninian has crap attack, good speed, crap defense, okay resistance, and has Light Breath for buffing allies.

obviously Ninian have an advantage on Dragon Emblem.
Sapphire Lance is a pain to Red units, but Ninian can have Triangle Adept and a Breath Weapon.

I think Ninian is better, but there no guarantee that you will summom her(you know)

I thought Ninian is better she can have Lightning Breath and she have a good resistance and if you have an another dragon on your team like fallen robin she can give to him res and speed +6. And if you have a + res Ninian she can survive to Reinhardt :)

Ninian is in general a very good dancer for Dragon Emblem or just regular use. I have her, and she pulls her weight. Keep in mind though, that Bound Hero battle is a revival, so the banner won't return. You'll need to wait until she shows up on another banner to pull for her easily.

Ninian has her own style, both are just different.
But, maybe I'm wrong, the ninian and hawkeye BHB is a rerun, and the banner doesn't repeat on reruns, you just get the orbs from maps, and that is if you haven't completed it the first time.

With the Dragon Breath Refinery update I think Ninian became better than Azura.
Giving Ninian Triangle Adept removes the advantage Azura had, and since Ninian's attack targets the lower defensive stat at range, she would out damage Azura in a lot of cases

Both are great, and before the Dragon Refinery update Azura used to be better but now Ninian is stronger.

Well Ninian is a dragon so she'll give slightly more arena weight.