Just a simple question I thought about after trying AC3's multiplayer. Basically, what if the assassination contracts in singleplayer worked in a similar fashion as the contracts you get in multiplayer? You are assigned a target and you must take them out in the most discrete way possible. The amount of money you would recieve from these contracts would be determined by the quality of the kills and how "low profile" the whole ordeal was.
On a related note, what if the main story assassinations used this system instead of optional objectives and, instead of money being the reward, you would get "synchronization points" based on how discrete you were?
The reason I brought this up is because the devs always talk about making the enemies stronger to force players to use stealth, but I personally think this system would do a better job.