I agree with you Dusk, Equestria does need capable fighters to defend the freedoms they all benefit from. I do believe you when you say your OPs alicorn powers are used with a desire to protect the innocent. Unfortunately the desire to be an Alicorn may get a negative perception by other people as being from ego, I know in your case it is not, but who knows what other people truly want? though personally I think it is not my business to go prying into the heads of other people, whether their daydreams are dark and dystopian or not, they're not harming anyone for merely thinking.
Plus I would not know what to do with all that power, sure, it would be cool to be an alicorn, but unless Dawnshine Wonder was a trainee in the Wonderbolt and in my fan fiction I was working on, Dawnshine Wonder is not, those powers would probably be wasted. Plus I would not want to be susceptible to corruption, a guilty conscience from hurting others is not something I'd want, hurting others period is wrong.
Your OP Dusk Haven may be into heroics and that is endearing
however there are other things in Equestria that need taking care of as well, what Fluttershy does, taking care of animals, that is helpful as well because a respect for wildlife and ecology starts with respecting innocent creatures within their habitats, remembering that the world we share works by a delicate balance, like Earth, Equestria's survival in MLP fiction depends on how its inhabitants treat each other.
What would your cutie mark be? mine would probably be something like the wheel of reincarnation. In my MLP FIM fanfic, my OP, like countless other souls in various timelines, gets reborn into different worlds, Equestria is in a magical realm, beyond that is a paradise dimension if essences of beings completed their life lessons of unity and friendship. It's only a fantasy, but I do wish that it could happen, one motivation for that is I'd like to be in a realm of happiness and peace with everyone, no one is so lost in their ignorance or depravity that they cannot be redeemed, I'd like to think even beings like Chrysalis given enough time would learn the error of their ways, she was not redeemed in the official show, but I wonder how it would happen if she did.