Hi there. I'm MS_Ookami, a consistent Pikachu from Orlando, Florida.
I'd like to voice my opinion on the first few MUs discussed.
Regarding Pikachu vs Link:
While Link has a disjointed hitbox with his sword, Pikachu doesn't struggle against it as much as he does with other characters such as Marth in previous iterations or Shulk.
Pikachu has the speed to penetrate Link's camp game very well, and Pikachu wins at close quarters very dominantly. Our offstage game against Link is still stellar and we can use it to abuse his recovery game, much like before. We juggle Link very well and we have an option for just about any physical move that connects with our shield.
Link has a superior camp game and a disjoint as well as anti-juggle tools such as his d-air and bombs, which makes it difficult to keep him in the air. A well spaced Link with a solid camp game also makes it very difficult for Pikachu to stay at close quarters with him.
I say the MU is 55:45
Rosalina is tricky. Through personal experience, I have never lost to Rosalina in tournament.
Pikachu is fast and breaks through the wall-like defensive playstyle that is popular with Rosalina players. QA is great in this MU, allowing us to quickly rack up damage off of small conversions. Rosalina also has a very big hit box, combined with being floaty AND light, which makes ridiculously easy to juggle with our already amazing u-air. B-air makes quick work of her recovery and forces panicky Rosa players to recover over the stage with strong punishes. Dash attack can knock Luma off the stage from the very middle.
On the other side, Pikachu is also very light and is susceptible to dying at extremely low percents to Luma u-air. Luma punishes very hard when they have the read on QA as well. Luma acts as a shield and blocks thunder jolts, which is one of our most reliable approach options, and the brick wall that Luma presents with jab cancels makes it very difficult for Pikachu to get past it.
I say it's even. This is a tournament match of me vs one of the Rosa's in this region.
https://www.youtube.com/watch?v=JvawneeoWhY