The "shout the name of the move" thing is neither here nor there, I think. Overwatch isn't a fighting game, and voice lines like that aren't common in shooters

The "shout the name of the move" thing is neither here nor there, I think. Overwatch isn't a fighting game, and voice lines like that aren't common in shooters (Japanese or otherwise). For the rest, I'd guess it's a simple matter of Blizzard not having anybody in house who can check content. They've never done JP versions for any of their games, and the mistakes they make tend to be of the "copy/pasted from Google translate" variety. Also the 3rd-party localizer in the interview mentioned Blizzard asking him to check their Japanese, even though that would have been pretty late in the process. (One also suspects that the JP voice lines may largely be the work of the voice actors. That would explain why Genji (voiced by a native speaker) has tons of Japanese voice lines, while Hanzo speaks only English outside of his ult.)