The only really active and used zones are
1) Cortez
2) Omicron Zeta by nomads.
Gallia+Taus got a big hit with the moving of farm zone to Lorraine - besides one guy nobody uses it anymore, a lot of PvE and PVP was lost because of this and nerf to payouts where "standard" PvE zones were made unviable unless you shoot all factions or it's Cortez one. My proposal is to have cortez treatment to all so native factions can farm them, and then have one (One) zone bi-weekly or monthly with boosted payouts for cap multiplier in the system at old levels for shooting smaller stuff. You could add Rewards plugin on top and have a huge lucrative battleground system.
Speaking of Gallia - cutting ores any further would get boring. Something happened to 23 ore route and nobody mines it anymore, but Mil Sal, Molybden and 53 ore whatever that is are cool for flavour and easy to contest and used by unlawfuls. (first one is 22k from unlawful base, second one is in a pure bottleneck system with one JG and bases on one side only, and third one is pretty far from dockable stuff with no closeby PoBs)
How to concentrate activity
Simple. Take old Delta, use it as an ideal way to concentrate activity
1) ALL factions had goodmissions. Including Nomads
2) Freeport with awesome Mission ranges for everyone
3) Circular design with overlapping mission zones in the middle, and no obstructions and open space
=> I was baffled by that change then, and I am still baffled by it now. And now we have to re-invent the wheel.
EDIT: Azurite needs a big buff as you are raiding iota every time you mine
I'm talking Double normal CSU numbers, and you can make NPCs stronger.