so, we have reaced the point now that minecraft has an extensive collection of matter in the form of solid and liquid, mods add a bunch of liquids too, it all plays nice. but matter has 3 main categories( 4 if you count plasma ), solid, liquid and gas.
i think minecraft forge should add in the support for gas, because right now there are a few mods out there that have a gas system but as usual, if minecraft forge would make it would be much more stable.
this gas would not only be used for transfer between machines, i am seeing a vent wich lets gas into the air. like a toxic gas that will hurt or kill people in it. of course the gas would just float off(disappear) if you dont contain it. so build a room with a door and a vent, trick your firned and get him in there. turn on the gas and have a fantastic time!
this was just 1 example of whats possible. maybe the galacticraft mod will use this system instead of their "not so stable" oxygen system right now
let me know what you think!
PS sorry if this has already been suggested, but maybe i added extra content to the idea or made it more clear.