Voiced protagonists are not new, they've been around since the days of the NES. We all know what they're like. And the mainline Persona games had silent protags too; Joker in Persona 5 had two lines in the entire game that weren't chosen by the player. In the end it comes down to preference, whether the players want voiced or silent. I've always seen Dragon Quest as a haven for those who prefer the silent protag. Get rid of that haven and it becomes harder for us to find the games we like. There are plenty of voiced protagonist RPGs. I don't see why Dragon Quest has to be another one.
Silent protag all the way. It's one of the main points of Dragon Quest and if you don't like it, there's plenty of other great RPGs to choose from. A mainline Dragon Quest game without the silent protag wouldn't be a Dragon Quest game. You can make a game darker without drastically changing a series' formula.