Pandazoot has created a thread that points out some of the possibilities an open ended mission structure could have: How to rob a bank
, and personally, I hope a majority of the missions are set up like this.
With the added feature of making calls on the cell phone, the choice factor gets a boost. Who are your friends? Who can you count on not to double cross you?
Making certain decisions in early missions should have repercussions in later missions, like 'that guy you chose to kill in the third mission...his son is back for revenge in the 78th mission, and he's pissed', things like that.
And again, failing a mission should be just as significant as passing one. None of this, fail and retry BS; you fail that's it. It always struck me weird that if I failed a mission, I would be presented with the same cutscene. Not at all naturalistic.
EDIT: I expect to see a red star rating in 3......2......