You may have gotten this before in the past few days, but I have an issue with your translation of "Kamen Rider Oga".
That being that it's incorrect.
Orga is not an alternative spelling, it is the actual spelling.
On Souchaku Henshin toy boxes it says "Orga". With a very clear capital R.
The pictures I've found are small, but it's clear enough that you can see it.
But I would say this case that popular opinion can be thrown out. Most fans and even staff at Toei and whatnot probably have never thought about what the best spelling for Oga would be. They either chose the most basic way to romanize it or pulled something out of their ass and then it stuck because that's the only way people have known it.
Well, a lot of people thought slavery was a good thing and that the sun revolves around the Earth. Sometimes the masses have got it wrong. To get scientific on this, no one would ever argue that fact is created by popular vote. Nor would anyone argue that one's opinion is more right just because he's got a lot of friends who think the same thing.
To get a the heart of my reasoning, Orga just doesn't make any sense. There's no R when they chant his name. It doesn't represent Omega or King or anything. It just looks like someone saw the dash in オーガ and arbitrarily filled it in with an R. Probably a toy maker who was working independently from whoever created the character or some executive.
Oga and Ouga both represent the thing they shout. Plus...
Oga makes sense since it's O + ga. You see a lot of O's in the movie when he appears. And his transformation command is 0 0 0 which also looks like O's. Plus it looks like an abbreviated Omega
(O _ _ g a).
To take another example, in OOO, the O Medals are spelled the same was as the O in Oga in katakana. No one would ever write Or Medals, since the dash represents a long vowel, not an are sound.
Ouga makes sense if you imagine the kanji for it as being 王我 which means King and Self. (So Pysga would be Psi and Self). Since these are known as the Emperors' Belts, this sort of sounds right. The only reason I wouldn't go with this is because if they wanted to use kanji, why not just write it out in kanji? I saw one site that supports this theory, but the evidence for this seems a lot weaker than Oga.
Sorry to guys who are just used to it being Orga. But just because you liked something the old way doesn't mean it's better. Letting go of an old notion and embracing a new (better) one is all a part of learning and bettering oneself. Unless I missed something, there just isn't really any real evidence that supports Orga. Our jobs as translators is to convey meaning, not reenforce people's ignorant notions.