I think lower level players just got upset because neconu's were added to Land Area. I remember they were very hard mob when I was noobier.
One reason I Think land areas should be reset, is that the latest years land owners has begun with a land area with a certain mob on it, in some times rare, and then they've added a DNA of Another mob that they accidently got their hand of.
One of the first examples I remember was, back in VU9, a land area in far North of Amethera. It was acquired by someone I haven't Heard of before; it felt like a brand new player with lots of Money. The land area was pretty much as far from a teleporter as it could get. It had nice, big, fouls, including a natural spawn. Land owners were holding events there. Then the fouls were depreciated and instead there were fungoids, Another unique spawn. Then, the without a warning, the land owner sudddently also added atrax stalkers into the land area. And a couple of months later land owner sold the land area.
Another thing: As a hunter, I don't like the mix with regen and aggro mobs/high damage on same spot. Ok, now looting system has changed, but in the past it wasn't fun dealing with a mob that's biting your armor continously while you're fighting Another mob that would regen if you stop shooting at it.
Another land area that was a pity: In beginning of missions, there was a daikiba mission. There was one spot at sweat camp that was overhunted, but there also was a land area with nice daikibas. However, the daikiba land area was useless, because it also had argonauts on it (added by land owner). Though the argonauts wasn't a Life hazard and were fewer, they had longer aggro range than the daikibas, so if you tried to hunt daikibas on the land area you would constantly have at least one argonaut on you.
As for mixing Atrox with Neconu for professional players: Let me be wrong with this, but I Think those who hunt/can manage being swarmed by several atrox stalkers, or big neconu, are hunting what they are hunting because of loot composition or "Waves"'; they have gotten where they are because of specific knowledge; having to kill one neconu for each atrox (or other way around) is a waste of loot quality.
The management of land areas is of course the concern of the ´owner´. But, if land area spawns are getting unhuntable, don't ever complain about "unfair competition" if/when MA adds free spawns of the mobs somewhere else, especially if it's being asked for by the players.
I should add, I'm not much of an atrox grinder myself. I can kill one or two for fun if I come across one at a location where I won't be swarmed if I try. And in the past I've been in a few neconu events on the White Island because the land owner was kind'a nice even though those neconus was slightly above my general grinding level. With that, i just want to say, do whatever you like with the land area, as it's not one of *my* favorite mobs. Just that... in some other cases I've felt kind of sad when someone gotten across one very nice and rare DNA, they happen to have a land area and they put the DNA there, together with existing mobs, that way ruining two mobs. (Again, I don't have much feeling for atrox land area; back in VU9 there was like 3-4 Heavy marketed land areas with atrox on them and one of them even had atrox/atrax mix, and neconu was first the Atami land area and then Skalman's land area).