Forgotten has always been a stand out song to me when it comes to the bass work. Surprisingly, though, I recently learned here that Phoenix may not have even recorded that song. It could have been Brad or Rob (?!), maybe even the stand-in while Dave was working with the Snax.
On the recording you hear on "Hybrid Theory", the bass on "Forgotten" was played by Ian Hornbeck, one of the two session musicians called in to fill that role throughout the album.
I think it's just a result of them trying to go for that "raw" sound. I think they got it right with Guilty all the Same, but sometimes I wonder what other songs on that album might sound like if they recorded it like Victimized. War, for example, I think would benefit.
All 4 Snax members rap on that song. It goes Fiore, Dave, then the other 2 guys (I forget their names off the top of my head).
I hope they will include some more prominent bass work in their future albums, as I also think their music often lacks in the deep sound layers.
As a guy who absolutely adores Muse, I unfortunately don't think we'll ever see Phoenix doing something along the likes of Hysteria/Futurism/The Handler, etc. It's just not a part of LP. That being said, bass has never really been a shining aspect of the band's music. Hell, usually in most songs if it's not the only thing playing you won't even notice it. It's always buried deep in the mix. My favorite basslines are probably ETR, Forgotten (despite him not recording it on HT), RU, and MTG. Unfortunately there's not many songs where the bass strays from the root notes but there are some cases.