Hey i love this game , really and while playing i've got some ideas :

- what if with your dwellers you could invade place on a map (raiders camp, other vault etc...) and see the actual invasion ? that would be awesome right ?

- what if you could do a specialisation of your vault ? like building a special room that will modify your whole vault or just gave you more special rooms.

-what if you could echange stuff with your friends or even invade them (if your dwellers die during the raid you have to pay for taking them back)

-what if you could have some dangerous dwellers that would murder the other dwellers when they go crazy ?

Voila , that's all the idea i've got