I think that the "pass around" method needs to happen in addition to the methods of transparent protocols that occur behind the scenes.  For one, there's a lot of CONOPs that need to be worked out by getting knowledgeable people using it, and providing feedback about how it could/should/will be used and how it could be improved.  The pass-around method is simpler to implement and still usable by the types of users that will be using it in the beginning -- experts.  Also, I see that for very large, important multi-sig tx/contracts/escrow, the "manual" method might be preferred -- much the same way many people prefer manual-transmission cars even though automatics are "easier" -- some people/organizations will want the control.   

I'm all for protocols that enable higher-level access to this functionality, I'm just saying there should be lower-level access, too.