Noisepurge
Member
It's hard to believe that it was a conscious design decision. My guess is that it was a budget issue. Konami has been shown to be pretty stingy with its money in recent revelations, and Keifer was probably more expensive than your typical video game VA actor.
Probably the same issue as Destiny had with Dinklage. Hollywood actors are hard to get back to the studio to record more stuff.
They had the original recording sessions to do tapes and cutscenes that were planned long ago, then during development they couldn't get him to the studio anymore.