RelaxAlax did a Know Your Moves on Rosalina.
Unlike most YouTuber theories on Rosalina, I overall feel fairly satisfied with this. I do have some criticisms though, mainly:
-He glossed over her moveset inspirations, making her sound way more "made up" than she actually is. Mainly, I'm surprised he didn't even mention how her normals are inspired by dolphin tricks. What's interesting about this, is that it could be tied to how she was a Water element character (and later, Water/Light) in Puzzle & Dragons: SMB Edition. Also I don't understand why he thought to correlate her Down-B to Mario's spin since, while it could draw things in, it wasn't the primary use and wasn't used much. However, one of Rosalina's signature abilities is her gravitokinesis abilities, which seemed like the obvious inspiration for her Down-B, if you ask me. One of the Custom variants even draws in opponents, which could be a reference to how she could pull Mario back to the Observatory if he jumped off it. I always saw the cursor as just a visual easter egg, not as "she's using a variant the spin move from Galaxy". It's still clear this is Rosalina using the move, as the cursor appears to come from her wand in Smash.
-He glossed over the potential reasons for her inclusion (mainly, it seemed like he really didn't want to admit that she really was the most sensible choice for a Mario newcomer from a popularity and significance/relevance standpoint). I can't blame him for this one though since she's the ONE newcomer Sakurai hasn't made an official statement on regarding her inclusion, but it's pretty easy to piece together if you know the character, mainly the reasons why she is included in OTHER games, like 3D World (since her appearing as playable in 3D World was just as big a deal, if not more so, than her being playable in Smash).
-Some of his details on her lore and history and what not are a bit sketchy.
Overall, you can definitely feel this was rushed to squeeze everything into a roughly 10-minute window, but it's still nice and it has good comedy at least (it made me happy to hear him say "she's OP in Smash because she's OP in everything else", because that's so true, haha. Well I wouldn't call Rosalina or any character broken in Smash 4, but she definitely feels so powerful, and it shows in her performance).
I wouldn't use this video as some definitive source on Rosalina's inclusion in Smash or even on the character in general, but it serves as a good jumping off point for people to get interested in the character and maybe do some more thorough research themselves. Kinda like the equivalent to Wikipedia and DYKG.
I won't get annoyed at one's like this. Sure, it's far from perfect, but I understand that, A) pretty much nobody else is willing to do near as thorough research and analysis on this character as I do, and B) he had limited amount of time to fill in the video, and he does this as a hobby too.