Eh, Mordin bugged me. To make a long story somewhat shorter, in ME2 Mordin spoke passionately in defense of the genophage and his work on it. He was legitimately proud of the part he did to ensure galactic peace while also giving the krogan a chance. There were good reasons backing up what he said, including exhaustive research he participated in. And unless you were really Paragon, Shepard tended to agree with him. The writing is good, so both sides have merit, and players can decide for themselves how they feel about the genophage, but Mordin's opinion at least is clear.

Then out of nowhere in ME3, no matter what you said to him in ME2, the genophage is a barbaric crime and he's horrified with his part in it and obviously it has to be cured and you're a monster if you disagree. What? I get that for narrative purposes, they did basically have to cure the genophage in the third game, but they didn't have to pretend it's a completely one-sided issue. It's not.

The writers did the exact same thing with Cerberus: in ME2 there was ambiguity and good arguments on both sides. There were shades of gray. Given the many changes from ME1, not least the continuity errors, it was easy to separate ME2 Cerberus from the weird "Alliance black ops group" in those ME1 sidequests. It was clear the Illusive Man really did believe in helping humanity. Etc, etc. And then minutes after ME3 starts, and throughout the game, it's like the writers are shouting at you that Cerberus was always 100% pure evil and you were an idiot if you thought they had some good points. It doesn't even matter what you did with the Collector Base; as soon as you set foot on Mars, the Virmire Survivor is really in your face about Cerberus, and you're basically limited to telling them "I always hated them!" or "ugh, they used me, those evil bastards!" Not to mention the game actually punishes you for not scrambling to put as much verbal distance between you and Cerberus as possible. It would've been nice to have the option of "you know what, Kaidan/Ashley? You were being an asshole on Horizon and you're being one now. Cerberus accomplished something crucial the Alliance didn't. And I'm your commanding officer. So cram it up your cramhole."