MitrasH I've won on Mirimar with the Vector + Mini before the update, and most of my 11 kills that game were with the Vector. I know what you mean about the wide open spaces, but that's why it's good to pair with a DMR. The Vector has better range than most think, just keeping it on burst helps a lot.
The "AR" in AR15 doesn't stand for "assault rifle" no matter how badly some people would like to believe. It stands for "Armalight- Rifle", named such for the company who originally mass produced the firearm. It is not even remotely close to being an "assault rifle".
