To be fair, last time I played Skyward Sword (7 years ago!) it was in Hero Mode because it was my second playthrough on my original save, and in that mode you start out with the fully powered skyward strike which one-shots everything up to the first mini-boss.
Anyway, after finding that even Deku Babas were hard to kill with skyward strikes I decided to apply SCIENCE to it. While I can't compare against the Hero Mode version (my Wii refuses to read my original Skyward Sword disc), in Skyward Sword HD I'd just reached the first upgrade for the sword, which lets me do a before and after comparison. I just need a willing volunteer...
Oh hai Quadro Baba, do you want to take part in some research?
I don't think Quadro Baba liked taking part in the research 😅
And after conquering the Ancient Cistern and finding yet more Quadro Babas to contribute towards my research, the shiny new Goddess Longsword now slices through a Quadro Baba in 2 slashes, one stab (critical hit?) or 3 skyward slashes or skyward stabs. Nice! It still takes the same 30 frames to charge up though, but the upgrade has doubled my attack power overall making skyward strikes more useful, even if they're still less powerful than just wading in and whaling on baddies with the sword.