Not sure if this has been discussed since it's a bit hard to search for a single character.

X: 1982-1992
X Japan: 1992-Present

Should all of the stuff released under the X name be on a separate X page?

I was thinking of the same kind of thing for Hizaki Grace Project. Hizaki just used the name Hizaki until 2006 when Hizaki Grace Project was formed.

Then the same should be done with S.A. Slayer, Overkill L.A., Warning S.F., Wrathchild America... no, I don't think it's a good idea.

Do location-based name changes not count (X->X Japan, Slayer->SA Slayer)?

There is a precedent for it. As in, Mantas -> Death, Hellhammer -> Celtic Frost, etc. I'm sure there are other examples. But mostly it's just noted "also known as ______," as in the case of Suffocation, also known as Psychotic Deformity which was their name waaaay back in the day.

No, those are only geographical add-ons. It is the same as with different spelling of existing band name to avoid confusion with anoher band.

As far as I know they never released anything as Psychotic Deformity, which voids every possibility to get an additional band page.

Add-ons (be they geographical or otherwise) and small changes (umlauts, z for s or similar) only make it harder to find the information and causes confusion.

I think X Japan was only called that outside of Japan, in which case it's not even a name change.

Just to play devil's advocate... What about The Kovenant then?

I'm not surprised to see that example brought up. Obviously the rules are applied on a case-by-case basis and we can not provide more than general guidelines. While the name change in this case itself was a mere technicality - making a "cool" letter change and adding the article - there was a distinct musical change as well.

No, I'm pretty sure they legitimately changed their name.

I think it should probably be listed as both; I'm not really knowledgeable about their stuff but especially if the name change accompanied a stylistic change; it definitely makes sense.

I was just about the say the same thing. Also with Crown of Thorns/The Crown. These bands are split into two pages each (and both bands have even re-released older CDs with their new names on them).