I personally really liked 2B. Originally, I was just fond of her design (I guess that makes me a bit shameless), but as the game went on, her her the desperation of her character began to resonate with me much more. A2 was a little more bland by comparison. I can tell she was trying to channel Kaine's edginess, but I found it a little superfluous in this instance. 9S ended up being pretty cool to me just from how insane he got by the end of the game over the death of his comrade.
I really liked what we saw of A2 but the game unfortunately feels like it dropped the ball on selling her as her own character with an individual story that mattered. It feels like she's there mostly so 9S has someone to fight at the end. The terminal at the Resistance Base added some nice and much-needed context to her, but it still felt to me like there should have been more. I wouldn't say she's bad or a bland character at all, just doesn't live up to what she could have been. IMO she should have shown up more during Route A to better integrate her into the story.
What I will say though is it might get old if Yoko just keeps doing that same archetype again. Kainé, Zero and A2 are all pretty similar, I prefer any of them over the kind of purity waifu heroine we saw in the vast majority of JRPG's but I would rather not see him keep repeating himself.
EDIT: Also while there is an element of male gaze/sexualization to be criticized with 2B's design, I don't think Automata is anywhere near as indulgent with it as other recent JRPG's like Xenoblade 2. The worst part about it is being able to self-destruct to ogle her butt, but at least that's an optional thing the player will never have to see unless they want to.