>>719178056 (OP)
There's a lot of little reasons, like him having comical racist Chinese caricature eyes for a visor, the fact that he shows up out of nowhere, the fact that there's an ongoing galactic apocalypse and he wants to pointlessly fight Shepard despite them nominally having the same goal, or even the stuff you don't see in the game like him breaking into some guy's house and eating his cereal.
But the biggest thing is that you can't really have a "super cool mysterious rival" character show up at the climax of a story and then have them essentially be a random guy with no prior connection to Shepard. It would've been more fitting if this guy was in ME2 and objected to Shepard doing shady shit with the Illusive Man, or even if he was a character that "died" on the Suicide mission or at any other point. Mass Effect is often a game about making sacrifices and hard decisions, so this character could be the embodiment of that burden. But he's not, and was written by someone who uses the phrase "giggle squee" with no irony.
