>>41015160ゴウ and ゴー are functionally identical, and romanization systems for Japanese generally leave "ou" as just "o". I personally think it's dumb because not all proper information is conveyed through the romanization, but that's just how it is. Everyone, including those in Japan, spell it Tokyo, not Toukyou.
The character's name is clearly a play on Pokémon Go, but now it also functions as an actual name and just so happens to line up with Go Ichinose (who has had his name officially romanized as Go instead of Gou). This isn't just a localization decision either. If you play BW in Japanese with kanji enabled, the end credits are totally in English, and this was 6 months before BW was actually released in English.
https://www.youtube.com/watch?v=4AmhTXFQT18&t=37m7s>GO ICHINOSEtl;dr The character's name is officially meant to be written out as Go.
