User blog comment:ImaFanMan/How Stand Arrows Work/@comment-30439574-20180705210412/@comment-35892636-20180705235019

Actually, yeah, that's a good point! (I completely forgot about Star Platinum.)

Though- like you said- SP:TW isn't a requiem form, but rather a evolved form. Still, it makes me reconsider my theory to this;

What if it is possible to achieve new Stand abilities/forms without the arrows, however, the arrows can still help you do so? After all- Star Platinum is the strongest Stand physically because of Jotaro's overall personality. Combine that personality with strong desires- to both defend yourself and kick someone else's ass- and the fact Star Platinum had a A in potential as well as no real ability- aside from Star Finger- it's fairly understandable how Jotaro could've pulled that off. But, not everyone is like Jotaro nor possesses a Stand with such high room for growth. So for those that still have strong desire and mentality but not enough too force the change- Stand Arrows will help the change to happen. (Oh, and there has to be enough room for growth in their Stand as well.)

Another thing: Requiem forms are temporary forms and have nothing to do with the Stand's base form- be it in appearence, ability, statistics, etc. And- unless it's just a new slightly different change- no Stand has developed a significant brand new form without the help of the arrows. With the exception of; A, ACT Stands. B, Whitesnake and it's many evolutions. (Though, Pucci's Stands are an unique case.) So, maybe, Requiem forms are the only thing you can't acquire without an arrow?