Just because her mane is curly does not make her a pinkie pie and why would you hate on nerds, nerds are awesome :]
I like Twist, I love her quirky little voice and love that she looks kinda like a ginger. Mind you, I've met people that dislike her because for whatever reason they don't like gingers. Maybe that's why? Anyway, Twist is one of my favorite fillies and I don't quite understand the hate either :[
She is only a little filly and may not have noticed she was "ditching" Applebloom. I don't think Twist ditched her after getting her cutie mark I think Applebloom thought she would feel even more left out because now (or she thought) she's the only pony without a cutie mark that's going to be there. Didn't Twist still want to go to the thingy with Applebloom anyways? This is just my opinion of course though
I always thought it was the other way around- Apple Bloom got two new friends and stopped hanging around with Twist. At the end of episode 12, it's even shown that Twist is trying to get in again whilst the other three are dancing... So she still wanted to be friends.