I was asking in a more general sense. Since its pretty common for people to say they have to be X AT for "concept reasons"; As I said you can do what you want.
As to this point you have suggested now, damage potential, that is why they suggested Brute. Since your Firey Armor damage abilities will be more effective on a Brute. Since the damage is DOT based, and Fury effects DOTs. If this was a Bio or Shield question in the Brute subsection, the comments would be the opposite. Since the Scrappers higher scale would benefit from the +DMG of those two Powersets.