I wanna summarise my thoughts on the character a bit..
First of all, Sakurai and the team did an Awesome job with this character's design. Both her (I'm glad she's in) as well as an Arms character. They nailed it. I was concerned about how they could do that, hoping the character could move while attacking, as well as throw long range attacks in the air, and they did it seamlessly. Min Min just looks great including in how she fights. We knew there might be a mechanic to change arms, but they made it more fun than I expected, including for how fast someone can switch arms, and each one being unique enough to be interesting. It just feels like a fun character to use.
For the competitive side, I was concerned that the character would be slow and stuck to long range, but they actually put some fast kick attacks into the mix, and I think someone will be able to manage ok close-range even if it's a weak point. Besides the normals (which seem good), Up smash and Up B seem like good fast options out of shield, and even nair may be very useful. The chakram arm makes nair faster, so I think that someone may want to have it on hand for faster options (unless you wanna play risky)
Honestly, I've been wanting a character that can switch between weapons for a while, and this will also make for different playstyles. Overall, big win of a character, in my opinion