ATM land areas work well for hunters, mainly because the land owners can build up and maintain a good stock of mobs. So why not ask MA to allow land owners to provide similar benefits for miners? One approach would be to enable owners to construct and run Finder Amplification Masts that increased the chance of mining success for anyone prospecting around them.
Each land owner could then decide whether they wanted to emphasise hunting, mining or (on the larger LAs) go for both.
So- is there a version of this idea that is workable/desirable?
Don't think so.
What is the only good about LAs is that you may concentrate on the mob you desire, like, you pay the tax to save time and maybe gain more long-term by having shorter pauses between kills than by killing them without tax other places. And so on.
As for miners, some LAs might seem attractive because the territory it is on has good markups; it is sure everybody knowing about it would go and mine around it, but less will dare to enter the land, especially if it has many mobs around. So there is some escape from overmining this way.
As for mining, there really isn't any place for customization; IRL, people can affect and change fauna, here too; IRL, people cannot change the whole terrain, here too; Besides, if you may select animals that live there, ores cannot be chosen as the territory itself is as this mob, and ores- its loot you may get. Density is how much mobs are around, but increasing chances of find is like increasing the chance to loot the mob instead, so it's a wrong assumption you're having. The land is everywhere anyways, unlike mobs.
So overall, it would mean that in those territories, by your suggestion, MA would be giving away MORE...
which they, sadly, won't