There's an idea... bring POS refineries up to 90-95% efficiency.
Don't tie them to skills, that would require extra coding, and don't give them 100%. Give them a high enough refining rate (75% is utter crap) that they will be viable in places where stations aren't available, but don't make them better than stations (its less efficient to build at POSs, so it shouldn't be as efficient to refine at POSs, however the current refinery rates are so low they simply aren't used).

POS Refinery a) Again will make rorquals more common in w-space. Same benefits as listed above. The point about frontier mining in nullsec is something I'd like to discuss further. Before w-space my corp had a month-long NPC null adventure. We wanted to mine, being an industrial corp and all. Having no outpost access was a real pain, slashing our profits and contributing to our eventual eviction (refinery takes a lot of CPU/PG, hard to defend against caps with limited guns). Enabling 100% compressed ore refining would mean more corps would put up POSes in NPC null or even loosly-controlled sov null to mine untapped resources. They would be quite vulnerable with a refinery array online, again increasing the amount of PvP / POS bashing that could occur. Again this would destabilize the mineral market further than it has been now with the ore rebalance, as this would also increase the supply of rare minerals (why mine veld?)
POS Refinery b) Makes POS refineries much more viable while still penalizing their use over a station. This is probably the better idea as its impact in nullsec is much more limited, most corps will still compress and ship to an outpost. It would make w-space industry at least potentially viable, competing with HS markets would not be as impossible as with a 25% loss.

Alliance Array Usage: This would both encourage proportion of industrial POSes out there and simultaneously decrease the total number, as being able to share 1 array with an alliance means corps don't need to anchor their own POS for access to one such array.

I can elaborate on my ideas further in the forum section if people are interested.