Well, SoM and SoW differs the same way how AC2 and AC3 differs. They are pretty much the same game at the core. As a sequel SoW has more features and depth to the gameplay, but it comes at a price of more gridning if you want to 100% the game. If you don't really care about getting true endings or gathering every little trinket, you probably won't notice it.
D
Deleted member 19066
Used to know an interesting fact about the designer of the nemesis system... but forgotten it now..