Compared to 1.4.x, as far as I remember:
- Generation of oil lakes has been moved from "only vanilla deserts" to a list of biomes that biome mods can interact with, allowing the pools to spawn in desert-like biomes from EBXL and BoP
- Generation of oil lakes has been added to swamps (and thus swamp-like extra biomes)
- Biomes which spawn oil lakes have had their chance of oil spouts increased by 50%
- Oceans have had their chance for oil spouts doubled
- "Large" spouts (unsure of what is "large enough") have a 25% chance of the shaft going past the oil bubble down to bedrock, where an infinite oil spring block is situated that will generate a bucket every couple minutes
- Desert oilfield and ocean oilfield biomes were introduced
And yet I just asked my entire player base using a map made with recent buildcraft and we can count the number of oil spouts on one hand and most of them are over water. So I guess we're just not as awesome at getting oil biomes. And even if we're just unlucky, it seems rough to handle it this way because of the way Forestry dictates how people settle. Normal/Normal biomes are prized.
That's because Buildcraft's power currently works nothing like a pneumatic system. In fact, it works 95% like Industrialcraft EU. It is pneumatic in flavor name only. Thus, if the intent is to differentiate, then weird systems like this one get invented.
The EU model is closer to Pneumatic power. Pressure based power: easy to store. One of the very oldest forms of mechanical power, in fact. So old that victorians were even making coffee and tea with it. You should see the clockwork driven siphon systems the french had. Quite beautiful.