Recruiting Morinth.... why? it made no sense.
Renegade Shepard recruiting Samara? It made no sense.
The Asari not attending the summit? It made no sense. Bad writing theory at work. They clearly wanted to make it a binary choice. With the Asari present there would have been a neutral third option present. That was not the way of ME3.
Kai Lame - didn't work.
Udina - didn't work
Anderson - was his purpose in ME1 to make Shepard look smart? I know in ME3 it was to be born in London... twice.
The Council - It was a good idea, but it seemed its only purpose was to troll Shepard.
Kasumi - So much potential for a deep character. So much potential wasted.
Dr. Chakwas - this character was wasted. She should have had more lines.... "working on some files." Can Shepard ever talk about the nightmares with anyone? No... Shepard is "all discipline all the time" and can show no signs of weakness, even just talk to the doctor. No wonder Shepard was going crazy.
Starboy wasn't even a good idea. Go away. Just... go away.
The Krogan birth rate... seriously? You want to cure the genophage? lol. Yeah, with the Asari in attendance she might have mentioned the fact that the only thing that was keeping Wrex in power was the fact that Urdnot controlled the fertile females, and that a full cure would undermine his power base. "Perhaps a compromise of an increase in the fertility rate would be more appropriate. Besides, it still takes a few decades for a krogan to reach maturity to fight and this war might not last that long."
Wrex: "Hmmm. You're right. The other clan leaders might just return to the old ways. Okay, I'll accept your offer."