In a couple of parodies that I made, I think I made it clear that I was not the kind of fan who read the story, was deeply moved, and cried. Not to say you're wrong for feeling that, not at all!
A lot of the time, I can overlook the flaws of something I love. Other times, there are things that I may like, but can have a critical eye toward them.
My Little Dashie...is the kind of story that I WANTED to like, but just never could get that invested. And looking back, I really do see all the issues it has. I want to stress that I don't hate it. I don't think it's the worst story ever written, I don't think it's horrible, but I do think it's really overrated. But I digress. Here, I'm going to list a few things I see that are a bit of an issue with the story.
~One, is the protagonist. This guy is just one big pity party. I can understand when a character has tough times somehow, either in the past or the present, and they're sympathetic for it. Well, skipping aside that he's also a walking Self-Indulgent Self-Insert, and all he really goes on about is how his past sucks, his parents are dead, and how he lives in a crappy setting. He does nothing to help himself, nor does he seem to take care of himself. We don't know anything else about this guy, or anything. He feels less like a character and more like an avatar for the author. This is something in stories that I can't stand. Unless you're intentionally doing that to make it hilarious and bad, then it just doesn't work and takes away the character element. Just because you're writing in first-person doesn't mean it's YOU. We know very little, as I said, but it doesn't work to any advantage. It makes me wonder why we're supposed to care.
~Two, the use of Rainbow Dash. For one thing, this guy does not nurture her. Sure, he loves her, but he does not take good care of her in the slightest. She's there to make him feel better. She's there to love him, to comfort him, to give him reason and purpose. Not only can you replace Rainbow with any other character, or even a real-life child, but she is just wasted in this story. Not to mention, kind of out of character. I know she's "reborn" and has had a new life, but she doesn't seem to retain much of her personality. We're never even SHOWN any of it, we're just told through exposition. All we get out of her is how much she loves her daddy. Or when she's angry about discovering who she really is. But even then, she runs away, and then comes right back to HIM, to make HIM feel better, because he's the only one truly hurt. What about her? She's cooped up, alone, with NOTHING to do. Rainbow would surely resent this guy and feel restless. Sure, they get their own open space place, but she never is truly "Free" to do what she likes.
~Three, it relates a bit to Rainbow also. Children are a responsibility. This guy needs someone to take care of him, to depend on and lean onto. That's exactly what Rainbow Dash ends up doing. She becomes his emotional crutch more than his daughter. Because again, he loves her, but he doesn't nurture her. And the problem is, this is NEVER addressed or seen as a fault! Nope! He's the best dad ever and she loves him sooo much! I'm not a parent, and yet I can even see that he is not doing this right. Rainbow Dash is cooped up and isolated, practically depended upon by her own guardian, and doesn't seem to do anything else but be his loving daughter. Like I said when you could replace Rainbow with any other pony or a real-life child, that's how it feels. On top of that, he doesn't feel like what he's doing is wrong! He truly believes that this is all best for her, that he's protecting her, and that she's happy and he's her loving father. If this had been where it was meant to showcase that he is NOT the best for her, then it might've worked better. He could've learned an important lesson about raising a child and how it's not what he thinks it is. Children are not emotional crutches. They are dependent on you to help raise them, to guide them through life, teach them to be independent, and love them. Love isn't enough. Children need more than that. This guy really didn't seem to get that at all.
~Fourth, the conflict. He wants to protect Rainbow from the outside world, and from the ever EVIIIIL government who would dissect her. Okay, dude, that's just paranoid conspiracy theory stuff. Like the government actually has a branch where they dissect things. Yes, I get that she's a cartoon pony from MLP, but this could have been handled a lot better. It really just didn't make sense to keep her cooped up, and I wonder why she didn't protest further. She would not put up with that, not unless they were on her own terms. She isn't lonely, isolated, or frustrated. Nope! None of the issues are ever addressed. It's all hunky-dory!
~Fifth, when it ends, it's like the guy didn't learn anything. He got everything he wanted, except for Rainbow being taken away, without doing anything, and without truly learning what it means to be a parent to a child. Nope, just what it means to have someone to be right there, which shouldn't have been a child. This guy couldn't look after a dog or a cat the way he looked after Rainbow Dash.
~Sixth, the way it tugs on your heartstrings and makes sure to try that hard. Now I know that many works do have that element, and when it's done right, it's wonderful. But here, it really didn't work so well. At least not for me. Everything was all about him and how sad he was going to be, and how Dash belonged with him there as his daughter and him as her father. It's all just sad by default, and that's were sad elements are handled badly. When they're by default and not by actual emotion of the storytelling's execution.
And that's about what I can think of in why I take issue with it. That's pretty much why I make fun of it. Now again, if you like this story and were emotionally invested within it, great! More power to you! You saw it in a way I didn't, and that's perfectly fine. I just disagree with that. So it's not terrible, it just needs some work, and would've been better if Rainbow Dash weren't involved. If it had been a story about a man who takes in a child, raises them in this way, and realizes that although he loves the child, he's not right for them, and learns this sad lesson? That would've been even better and would make for a sadder story.
If I think of more to say about it, I'll address them.
Oh, you're wondering what I did like? Well...
I loved the location of their second home. I just am a sucker for those kinds of places. :D
He did at least gain motivation at the end to make his life better.
I did like that Rainbow retained some of her character when she was angry. Even though she came back for all the wrong reasons.
Even though he didn't learn anything, it was a good thing for Rainbow to go back to her own world and back where she belongs. I'm just glad he didn't refuse to let her go right in front of all of them.
There were a couple of moments between them that were all right.
Other than that, I really don't have much else to say. That's about it!