The VOX announcer seems like it has very limited capability that wouldn't be able to capture the variety of customised voice synthesis samples from the original game and further, I don't know if Valve would approve of that decision lol
I did suggest new synthesiser sources early in development to reflect the meta time period jump from 1980s to 1990s, but we soon decided that the original lines were too distinctive and iconic to 'Faith' as a whole.