Well. Again, I disagree. I have no qualms with anime ninjas and space battleships. If anything, anime has proven these things are awesome, and Kai Leng was ok-ish. At worst, he was forgettable.
The real problem in ME3 is a constant, dim, unwavering sense of grimness and darkness and emo self-pity and self-congratulatory bull**** that pervades the entire story. "Oh I can't even imagine how you must feel" was probably said a 100 times. "Only you can do it Shepard, I know it" probably a 50. And I'm not even exaggerating here. Monotonic.
ME1 had mechanical issues, but it was a good ride in terms of surfing through different tones and emotions. You'd go from "Ok, this is weird what is happening here" to "We're being framed!!" to "I'm a Spectre! I'm badass!!" to "We've got to find this guy now, detective hat" to "I'm bummed out we're gagged in the citadel" to "We're coming for you Saren!" etc., etc.
ME3 was just "We are guaranteed to be dead but we have to fight no matter what... this is so sad" for 30 goddamned hours. It's tiresome. And it creeps on you till the end. And then the end is an anti-climax, and people just went bat**** insane.