For me it would be Pinkie Pie or Applejack. Both of them have traits I would of loved in a mother, but never had.
Let's start off with Pinkie Pie first. Pinkie pie would always be able to make me smile even when I was feeling the worst, she could make me smile even when I'm the most frightened. A mother who is always there for her child and always can bring a smile upon my face. I always wished for that in a mother when I was younger and even now.
Now, Applejack. As a child and even now I absolutely love apples, so growing up on an apple farm would be absolutely great. Secondly, Applejack would be a great mother because she has such of way of calming me and making me feel like everything will be okay even when panicking. I could imagine her singing lullabies to me in bed after I just had a nightmare, another trait I wish I had in a mother growing up.