Mini-Gun has never really been treated very well in Fallout Series. Although the argument can be easily made that it was a good weapon in FNV, this is primarily due to how rare armor was and the fact that 5mm was Armor Piercing so basically it was very good weapon cause you were unlikely to come across anything in game that had enough armor to matter without some sort of Monster Overhaul that is.
People really need to stop it with magical legendaries...Those weapons will likely be removed in a serious overhaul anyway.
The point is that, at this moment the change of weapons for the better rests solely on players to make those edits themselves so it just is pointless having a discussion about game balance with players that don't have a lot of experience in that regard.
The problem is that Vertibirds have a mounted Mini-Gun, the purpose of said ship is to be a gunboat and to drop a small amount of soldiers, thing is at the moment it doesn't do either very well.
These gun-boats are relatively late game especially if you don't rush story. So by the time you encounter what should be a terrifying experience its really just laughable cause the gun doesn't do enough damage to kill anything that includes you the player. Cant see why people have a hard time understanding that you should be forced into cover the moment a Vertibird comes into play, and to make that happen realistically both its damage and Soak should be beefed up substantially. The troops it drops off come into play to flush you out of cover into mini-gun fire....That should always be death for non-PA characters that cant slip away or who didn't come packing a Rocket Launcher...
As it is now its heavily reported that V-Birds are just flying Lootable Containers that drop gifts from the sky. That doesn't seem reasonable even in "game balance" terms.
Yes all that can be fixed up with Construction Kit.
Thing is that even if we don't nerf the amount of 5mm or increase its value at venders the 5mm is still very rare to gather a lot of to even justify carting around a very heavy object like the mini-gun...The low damage it has right now is really just a slap in the face.
Gamers need to understand that now that Fallout 4 supports modding on console, your going to encounter new representations of how the game should be played and you wont have much of any other game out there to compare that against the new stuff that is coming around the corner.
You can expect stuff like this to become more vicious, loot to get rare, and new gameplay mechanics to become available.
In regards of the mini-gun less scripts to make it a better weapon is better approach...Cause your going to want less issues...A simple damage tweak doesn't hurt your game...Including a damage over time counter does sap your resources.