It's an incredibly difficult song and Moom did it justice. I agree with someone who said the instrumental was a tad bit high in the mix, and there are a few phrases that feel over-quantized/tuned, but considering it was a rush job that got done in "considerably less than a month" I think it turned out great! I'd love to hear a remastered version some day, but that's very unlikely.
What Mumei lacks in raw power -- she's not packing anywhere near as big a cannon as Suisei, let's not kid ourselves -- she more than makes up in the subtle shades of emotion that her softer voice lets her bring to the fore. That said, I don't know if the mixing did her many favors here; the instrumentation felt like it was still tuned for Suisei in that it wanted a more powerful voice clearly out in front. In my entirely amateur opinion, the instruments should have been faded back a little more so that Mumei could rise on top of them. Regardless, Mumei rose to the challenge that "Stellar Stellar" provides, and I think she's more than suited to it.
Stellar Stellar is a difficult song to sing well, it's fit for Suisei's voice and skill. Mumei did her best to cover this song and made a unique beautiful Stellar Stellar for us. I really admire that and enjoy this cover. BTW Mori said she MAY sing an English version cover of Stellar Stellar. She said she finished the lyrics already and waiting for the permission now. Thanks for this reaction!
apparently, mumei's the first to officially cover Stellar Stellar within hololive, let alone one of only two to officially cover suisei songs within hololive, the other being IRyS with Ghost. sasuga moomers
Some of the ppl in this reply section are mission a crucial detail about singing- Suisei is immensely talented, but you must remember that different singing styles will suit different voices. It’s not that Mumei lacks power, it’s that she’s putting her own spin on the song so it will fit her singing style and sweet clear voice. Apparently this one song had over 9 takes so you know she wanted to get it perfect.
I think you're thinking of Ina singing "Ghost" at Connect the World. Mumei sang one of Towa's songs ("Pallet" maybe? I can't remember off the top of my head)