While that is perfectly suited to /tg/ station, I'm sure, it is not for Paradise. Ideally, though this is not the norm as of late, the chaplain is giving sermons, counseling lost souls, gathering followers and generally serving as an RP-starter. This has been derailed by giving them a custom melee weapon round-start paired with a crusader-themed riot suit, with no real standards being held to them. Honestly, I'd like to see a hell of a lot more job-bans for valid-hunting as a chaplain or similar RP-based role. You are there to aid security in deconversions or other ceremonies and help erase runes. Stomping through maint with a holy sword seeking antags runs counter to what they are there for.
Now, allow me to take a step back and acknowledge this is not directly related to what you are proposing. Still, it makes the chaplain much more of a combat role, or at least in direct support to combat.
The Devil gamemode is a very interesting concept however, but probably best kept an adminbus thing, as opposed to being in regular rotation.