I agree. We desperately need fresh voices.
Since Sims 4 Basegame has become available for free with regular updates and seemingly no end in sight we could almost consider the game a live service. The game is a decade old, man, I'm getting truly fed up with the limited voice options. It would be wonderful if they could spend some money and resources on hiring additional voice actors! The game NEEDS it at this point, at least two different accents per gender, but I'd also love some extra sinister and ethereal voices for my not so-humans...
Perhaps it's worth checking out the TS4 Sound Tool which is available on Mod the Sims. I haven't really looked into it much myself yet, but apparently it lets you copy and edit/replace sound files, including voices, although these may or may not override the existing ones. It appears to be up-to date.
Link below:
TS4_SOUND TOOL