What i mean is buildcraft after you build your first quarry and processing factory there really isnt anything to do, because at that point minecraft mines for you. i mean try not to give too much to your users because after a certain point there is really no reason to play the game anymore. Industrialcraft is running into this problem with uu matter. It seems like its initially really hard to keep a good eu/t but after making a decent uu plant you can make 1000 windmills fairly quickly. and that gets you around 5000 eu/t. all im saying is since this is an all encompassing mod try to have an infinite goal at every tier of your mod. for example a ship upkeep minigame something like the nuclear reactors in industrialcraft. maybe something that requires two or more people to fix depending on the ship build. like repairing the reactor core or something like that. one player disables the shield temporarily with some sort of laser, while the other actually replaces the internal components. back to my original point though try not to make the game complete itself for the player. because then it would suck like most of the wii games that are out now