map idea help

ok ive been just playing around in the editor lately with terrain and ive made this...a nice looking city with 2 entrances/exits...lots of paths and areas...open forest (trees are touching so you can walk through forest)....a small area of water where there is some boats and a few assassins(as if the assassin just got dropped off by the boats)....

so right now i wanna make a map outta this...does anyone have any good ideas with this terrain setting...i was thinking something along the lines of this...

you start as the ninjas and you have to sneak into the city and assassinate people and stuff....thats what i want you to be doing but i have no general concept of the story right now or even an actual mission....anyone wanna help with this map???

How about an open map where there is no set objective. You could be Mr SuperHero and help out any and everybody who needs help, or you could be the mysterious person who does criminal deeds behind the backs of those that trust you.
How about you start off in the port as an immigrant to the city and have to earn money to buy a house. There are a lot of things you could do in a map like this.

yes that doesnt sound bad...but i wanted to make a 2 team sorta game...like 1 team is assassins...they have to infiltrate the city and assassinate some people...some high ranks or something i dunno...meanwhile the other team is hunters that have been following the assassins for god knows why...and their job is just to annoy the hell outta the assassins and kill them...while all this is happening there can be an open rpg feel...like you can find people that give you quests...this will be to level up and obtain good items...i think what im saying is a good idea....but i still need major help on gameplay ideas, how its actually gonna work and everything