To the entropy idea. Maintenance should be easy while control is still high. After a week or two of total inactivity, it should start to get more difficult again, until eventually it is controlled in name only, with no benefits to holding sov at all. Making it exactly as hard to keep as to gain forces alliances to constantly be on the offensive, as the defender has no inherent strategic advantages as you proposed.

This provides a counter to massive unpopulated sprawl. Done right, it gives an incentive to create coalitions of smaller entities than the current corps as the smallest level of entities organized, and scale in a less heirarchical fashion up to major power blocks, as a coallition with only a very few active systems would end up paying bills just to put a color on the map.

you're a bit late with your bad ideas OP.

occupancy based sov was requested by quite a few alliance leaders a while ago, so your ideas arrived late and don't make much sense, on top of requiring a big overhaul of planetary interaction. nulsec sov through control of NPC populations is not viable and has no place in the game known as EVE Online.

Check the date of the OP, please.