As much as I like this idea and think it would look way, way better around the ship, I gotta say I don't think it makes sense in RP. Every photo and every scene that I personally have seen from the movies or TV shows, even the comics I've read, has troopers with weapons in hand. At those times, however, the troopers are either patrolling, guarding locations or escorting VIPs, conducting military operations, awaiting the arrival of VIPs (such as the arrival of the Emperor on the DS) or have been deployed in potentially hostile locations or highly important Imperial locations (Endor). The few times you see a trooper without a weapon, they're generally:
A) Higher ranking than the troopers accompanying them
B) Accompanied by armed troopers
I think the big thing that's being overlooked is the troopers in the TV shows and movies don't have weapons off safety when they're off duty, but rather every instance of trooper we see in the movies/shows is ON duty. If they were off duty, I feel like they wouldn't be wearing their armor. They don't live in it.
Just my opinion, at the end of the day I could be dead wrong. I still think it'd look way better and make more sense in RP to have weapons on safety at all times rather than pulling them out of nowhere, but I don't think anyone's going to complain with "pulling that weapon from nowhere is failRP" when we have troopers running around with purple, blue or golden guns that are clearly not standard issue. +1 for DEFCON IV being used more around the ship, however. That to me would make alot of sense.