The playa in Saints Row does speak once. It's actually a bit odd when he does, solely because up until that point, he's a silent protagonist.
I can't remember which movie it was, but Hollywood wanted to market one of the Marx Brothers' movies with "Harpo speaks for the first time." He would say one word: Murder. I'd imagine Harpo Marx speaking would have had much more of an impact at the time than "playa did, but it's kind of weird.
On a similar note, I think one of the worst instances of an end to silence is Drakengard. Caim speaks in the beginning, but soon becomes a silent protagonist, his only mouthpiece his pact-mate. And she usually responds to his thoughts, rather than spelling them out. One of the endings, he regains his speech. What does this tortured soul say, after all the silence? After watching tragedy after tragedy?
"I AM CAIM!"
Dude, seriously?
Back to Saints Row 2. It's especially important the character speak because his (or her, now) role has changed. The original character was muscle for most of the game. He didn't have to say anything. Rebuilding the Saints and taking charge, it works better with a speaking character. Though it would have been cool if your character was silent in some cases. Imagine if all he did was stare, snap his fingers, and his Lieutenants took care of business. However, I think that novelty would wear off rapidly.
They could have done the game with a silent "hero," but with their direction, I'm glad they didn't.
In Samus' case, I'm hard pressed to think of anything her voice adds to the experience. It seems like a dicey situation to add voices to beloved characters because we've all imprinted on them in one way or another. I'm sure the "Harp Speaks" phenomenon can have a positive impact, but it's nothing short of a gamble. Unless your goal is to divide your fanbase, it's a bad idea.
Then again, it sounds like Other M did more than that to divide the fanbase.