I was OK with letting Alenko die in most of my playthroughs in ME1, not because I hated him he was always just a bit of a passenger for me and felt kind of bland. I haven't romanced Ashley in ME3 though so I'd like to see how that turns out, I think I'll wait for the DLC though before playing again.

I don't think she was anti alien so much as she wasn't used to dealing with them and was a bit ignorant, add to that her family background with the war against the Turians and that explains her general distrust. That can be changed by your dialogue choices with her throughout the game. As for her of you regarding Cerberus, I found that to be a bit irritating but she does trust you again depending on your choices in the game. So it all depends a bit on how you treat her.