How come there arent machines that use air?
ALL burn-based generators. Those are machines just like the processing ones, except that those are used on energy generation.
Soil is used by IC2 crops and other plants.
Because Greg never implementing anything like "this machine requires air to work properly."
Affecting IC2 crops is probably possible, but crops from other mods would likely be unaffected. So its hard to commit to something that will be half-assed in a lot of popular packs.