I'm sorry, but I don't see how it does NOT matter? If it were indeed intentional suicide (at least at the moment) that pretty much changes our whole perspective on how we view his life and works. Similarly, based on Percy Bysshe Shelley's suicide by drowning, the meaning of his later poems such as "Stanzas Written In Dejection Near Naples" take on a whole new meaning... particularly the section that alludes to drowning.
No, if there was something brewing in hide's mind, even in the BACK of hide's mind, it is of the utmost importance... of course, unless it isn't of the utmost importance to YOU (indefinate plural) are a listener/fan... in which case, we might establish that you as an audience have no interest in critically listening to his works. As I said, such ignorance only deprives us from a deeper sense of appreiciaton of hide's music.
I mean, while we're at it, let's just ignore the fact that Yoshiki's father committed suicide, and the sacrifices his mother made by selling the business due to her faith in Yoshiki's dreams... Well now, the whole legendary tale of X's success is starting to lose it's glamour a bit, no?
Anway, believe what you want, but I firmly stand by my philosophy that paying attention to both intrinsic and extrinsic literary analysis go hand in hand with being a true fan. Ignorance is bliss, but only very superficially.