Honestly, while I do like the instrumentals and such, I have very mixed feelings for Stack.
It took me like 15 listens to start loving Necromantic, and the vocals on that song have grown on me now, I like the vocals a lot.
Same goes for WARNINGxWARNINGxWARNING, took a lot of listens to get used to the vocals, but now I really like the song.
I just don't like the "weow", and just the "nasally" thing Stack does (listen to WARNINGx3, you'll probably get what I mean), although I do think her range is incredibly impressive, and as someone who sang in a choir before, I wish I had that range lmfao
And this coming from someone who likes IOSYS, and they have a shitton of songs which are high pitched and stuff like that (Scarlet Police, Cirno's Math Class, even Alice->Dere) and I don't really mind them.
Surprisingly I liked the new Flandre song immediately when I heard it for the first time, I just didn't like the beginning (because of the "weow" thing), which is a first for an Akatsuki song.
Although, I do agree that if I ignore the nasally voice, Stack can really be amazing, I was listening to Hanipaganda and holy hell, the "Hanipa Hanipa ganganganda" part is amazing, holy shit, the soft vocals on the funny dokidoki wakuwaku song are really nice imo (I liked those from the start), and she can really make me feel amazed when I listen to those songs.
So idk, like I said, I have real mixed feelings with Stack, but the instrumentals are really good.