Don't even get my started on the "monster" filter Smash 4 shoved on Dedede's perfect Brawl voice.
Wait, they recorded new voices for Mario/Luigi in this game? I was under the impression they just reused voice clips from Melee/Brawl.
Melee used the same lines as Smash 64. Those lines were ripped directly from Mario 64. Luigi was just a pitch changed Mario voice with some lines re-organized so people didn't know what was up (but we did). 64 and Melee did this for a lot of characters, it just took voices from their main game and re-purposed them. This sometimes led to hilarious things like Ganondorf only having one jump sound ("tch") and not having a sleep sound so he just makes a bear or boar or some animal sound bank snore. Which imo is actually great and fits Ganondorf and Sakurai must have agreed because Ganondorf still snores like a large animal when he sleeps instead of making human noises. So that's whatever.
Brawl finally gave the Mario Bros their own voices unique to Smash (and most characters, really). And because Brawl was a serious game for serious gamers, Mario and Luigi for whatever reason, were recorded with a gravely lower pitch voice. It's not as bad with Luigi as it is with Mario. Mario is just disgusting. It sounds like someone trying to pretend to be Mario. Or like, ol' Chuck had a cold. Either way, they needed to redo those lines badly. Or just go the Smash 64/Melee route and rip from Mario 3D World/Galaxy/Whatever. It's even worse in Smash 4 because Doc uses Mario's voice, so two characters have this garbage recording.
I imagine they told him to be super srs business with Wario too, we just can't notice it because Wario's voice is already low pitched and gravely.
And it's not like they're opposed to straight rips from other games, because Toon Link is still rocking his Wind Waker sound bank, taken right from the source.
I don't understand how they can go so right with some characters like Roy, Lucario, Wii Fit Trainer and Robin and then go and mess it up with Palutena, Mewtwo and some of the Brawl rips that desperately needed to be redone, like the Mario Bros and Bowser. Oh, and poor Jigglypuff still using her Smash 64 voice lines all these years later and it shows if you listen closely in sound test as how low quality they are.
But might as well redo Dedede's voice for Smash 4. Go right ahead and take a great voice and make it sound more "monster" like because villains can only make generic monster sounds. Not allowed to have personality with the villains. Like, seriously. Why?