It's actually a desire of mine for (nearly) every character to receive new voice work in future games, and better localized to English where necessary. Sound freshness goes a long way toward a fresh presentation. Anyway, here are some of my remarks on the voices in Smash 4:
- Villagers really should have vocalized. They could use an androgynous child's voice so that both sexes could use the same sound set. The silence just compounds the serial killer meme.
- Olimar could have done with more vocalization, but there's plenty enough noise coming from the Pikmin, so maybe that's why they refrained.
- Mii fighters are eerily quiet, but the sound designers probably didn't want to risk an unfitting voice that ruins your immersion in your character. Maybe if the next system updates Mii creation to include choosing a voice, the next Smash could tap into that. Maybe pitch sliders like you'd see in text-to-speech programs?
- Not particularly bothered by Bowser's noises. He sounds like he did in Mario 64 and MK64, which is what I was familiar with first.
- DK's gorilla noises are fine for me - they evoke his primal might, but I could still live with "ook ook" if they ever decided to swing that way.
- Diddy's chimp noises are similarly fine.
- Disappointed that Yoshi never, at any point, makes his trumpet noise from the SNES/N64 era.
- Any reason Mega Man doesn't vocalize, besides him supposed to be looking stiff and expressionless like his sprites in those games?
- We know now that Samus can still be heard, albeit with a filtered voice, while suited. It would have been neat if she could speak in Smash. I understand why they wouldn't do it, though - they want Samus and ZSS to evoke different personalities even if they are technically the same person, to further distinguish the two forms. Regular Samus spouting "Try me," or "You're mine" would cause a bit too much bleed-through.
- The Star Fox characters... what to do with them? They seem to change voice sets every time. As much as I loved the classic Star Fox 64 voices, when brought into Smash, it didn't let their personalities shine quite the way the Brawl voices did. Fox's war cries draw constant derision. Seems like a mistake to get those old VAs back for nostalgia's sake, tbh.
- Am I the only one who wouldn't mind if Marth received an English voice actor? They could "explain" the change as Marth being multilingual, learning the languages of every land he conquers.
- Little Mac, for being a Western martial arts archetype, makes sounds of exertion that sound more in line with a native Japanese voice; bit unfitting.
Come to think of it, Smash 4 introduced a few characters who don't vocalize at all: Villager, Mii, Mega Man, Pac-Man, and Duck Hunt. If they could conceive extremely memorable voices for the likes of Ness, Captain Falcon, and Marth, I wonder why a similar effort wasn't attempted with these characters.