That would be interesting. Story spoiler for players that have never touched the game, but Ninian does transform within the game's story. She was basically taken control over by the game's main antagonist. She's not a playable character, unlike her brother Nils, which like Ryunosuke said.
There are different 'tunes' the player gets a hold of that can bolster the character's Defense/Resistance and their attack as well. Dancers had the ability (though severely limited) to buff a hero.
I think they would need to make a whole new category since the laguz don't use breath attacks at all aside from the obvious dragon tribe. In general I feel like there's a lot of stuff they need to think about when it comes to adding the laguz. Really looking forward to what they come up with though.
Yeah, that's true. At first I thought "well... why does that matter?" But it could make inheritance tricky and confusing. Then I thought maybe a whole new colorless category that is "laguz" but then there'd be four colorless types and only three of each of the colored types.
Plus, there's a lot of colorless units already. Could make summoning a nightmare. But, it might make colorless more viable. I don't know.
For now, my vote is Nils. I forgot about him. I mean, I knew he exists, but I... anyway... all I could think of was that one girl (tethis?) And the herons.
Laguz would be an odd addition, but if it followed as it did in the previous games:
*Dragons would be weak to thunder (blue)
*Hawks/Ravens/Herons would be weak to wind (green)
*And Tigers/Lions/Cats/Wolves would be weak to fire (red)
*The meta would shift considerably
*Reinhardt and Olwen would mercilessly wallop the dragon tribe.
*Sanaki and Lilina would maim a lot of the beast laguz.
*Nino and Sonya would maim a lot of bird tribes as well, so...
So, hey, get your Grani's shield ready kiddos!