I think the fact is, Cabin Crew should be able to open and close doors. It gives us maximum usage which can get us used to the doors (OK so it might be slightly different in an emergency with power assist and harder to open due to slide being armed but still.
I have heard the 2 most notorious aircraft for inadvertant slide deloyments is the Airbus (shorthaul 318/319/320/321) and 767. Because either the arming lever moves in the same way as the opening/closing lever (A320) or the arming lever is right above the door handle (767)
One way that our airline (a certain UK airline - not sure if other airlines do this aswell) prevents this risk is to have a strange procedure when arming and disarming 767 doors - 2 crew members do it - 1 of you puts your hand over the red control handle whilst the other arms/disarms. This is designed I think to prevent crew members ''accidently'' opening the door instead of arming/disarming. (This is if there are 2 crew members per pair of doors available) It does make it slightly awkward and is abit of a song and dance, and the lever is quite stiff as it is, but I suppose if it is to prevent inadvertant slide deployments then so be it!
I think to prevent it, the best way is rather than making ground staff open it is to let crew members open the doors, but just stress the importance to crew of check check checking!!! Things like double checking before opening and checking all indications (like the Emergency Only placards/or no placard visable/yellow flags/no yellow flags) etc etc whilst cross checking and also before opening is the best way to help prevent inadvertant slide deployments.
My airline lets us cabin crew open the doors, and I think it is the case of most UK airlines.