Since the Japanese version uses vocal synthesizers for the voice acting of the Accessories and Proper-kun, and they actually use your created name in dialog, they're pretty much bound to whatever synthesizer programs already exist, and licensing those out.
If you want to play around with some, this is the company Atlus Japan licensed synths from for the Japanese version of Catherine. Show was the narrator, Julie did the boss announcements, and Kate said "Edge" (which is still in the English version). 2/3 of these voices were replaced with actual actors in the English version. Not possible with Freedom Wars.
http://voicetext.jp/
English synths just aren't as malleable as the Japanese ones in this case. A lot of them don't have pronunciation consistency, and with a fairly large script of original terms, that's definitely an issue. It's not so much lazy, just unfeasible.