The thing is, most villains are seen through the eyes of the protagonist when it comes to videogames. They're the bad guys, the ones whose personalities bounce off of the main character. Not many games let you take the viewpoint of the bad guys because the real spotlight is on the protagonists, else why even bother playing the good guy? Is there a story where you get to play as Bowser, see why he steals the princess, how he does it? That could provide some insight as to how he works as a character. But, for the most part, the main focus is typically on Mario's escapades (it was nice to see him teaming up with Mario in Inside Story and RPG though).
In games that are heavily fueled by narrative investment, having a rounded antagonist is super-necessary. And when it comes to that type of investment the game is putting half the burden on the player to make and commit to choices they believe affect their experience. Having characters that are somewhat identifiable, even in appearance, makes a big difference, but their actions are key. Going to the extremes of what one person is willing to do can be a fascinating story, sure.
The biggest issue lies in how much the player is able to put themselves in the protagonist's shoes. When you play as a hero archetype, you're not only playing the good guy but casting yourself in an idol's position. Link is a hero of time who just wants to help out the people he can (disregarding the superfluous property damage). Lots of people want to relate to that. However, when it comes to downright villains that do the things you listed, it becomes harder and harder to identify with them. I think there'd be a tipping point between dissociation with a character that is irredeemably evil and identification with a sympathetic (or at least understandable) villain.
TL;DR: So, yes, playing as filth can provide a unique standpoint, but it's way more fun if said filth is well-characterized, has a reason or history for doing the things they do (I wasn't sure if that went without saying). And perhaps seeing the bad guy win wouldn't be such a bad thing to experience every now and again.