Besides the unnecessary trolling in the trailer, I was really pleased with this reveal. Rosalina was by far the best fifth representative for the Mario Bros. franchise. (or sixth or seventh, counting Yoshi and Wario). Sakurai also did surprisingly well with her moveset, from what we've been shown. Her model and play style seem to fit in just fine with the Smash cast.
From a very, very, very premature competitive standpoint, here are some general thoughts:
+ Luma acts as a dispensable Nana that offers (seemingly retarded) range and presence. Can be revived an infinite (?) amount of times with the wave of a wand, but seems easy to kill off.
+ Juggling and follow ups seem to be a natural part of her moveset
+ Her recovery is above average in both horizontal and vertical planes
+ Utility is granted in being able to block/repel projectiles
- A little floaty
- Seemingly lightweight
- Her knockback seems to be produced only from Lumas, whereas the hitbox on her person is much less powerful as far as launching is concerned
And to anyone who's worrying that she's going to "replace the Ice Climbers": Nope. She won't play much anything like them. Their only similarity is that they have a dual presence on the map. But this duo will likely have no grab game (Luma is more of an tool than its own entity) and will likely focus much more heavily on combos and zoning and the like.
Anyway, I'll say again that I'm very pleased! Sakurai chose a great character and executed her adaption into the series flawlessly. This also means no Bowser Jr. or Waluigi, which I'm just as giddy about.
GGWP everyone