It's so weird to me that they think this would alienate western ace attorney buyers. Does it have enough mainstream crossover for Japanese settings to be a deal-breaker? Surely everyone who still buys ace attorney is basically a weaboo and would be thrilled to get their feudal Japan on?
It's almost as confusing as human beings spending money on crash in the year 2017.
What's funny about DGS1 is that only the first case takes place in Japan. The remainder of the game takes place in London (one case occurs during a travel to London). I haven't played DGS2 yet, but given the pre-release information I think it's the same setup.
So to this day, we really have no idea why they never localized the title. Especially with a globally recognizable character like Sherlock Holmes in it.