From the Magus of the Moon release note:

If a nonbasic land has an ability that applies "as [this land] enters the battlefield" or that causes it to enter the battlefield tapped or with counters, the land will lose that ability before it applies. This is a change from previous rules.

Seems more intuitive to me.

So non-basics will ETB as Mountains. Will this change matter in the long run? Shocks can be played as untapped Mountains and Dark Depths won't have any counters but will be a Mountain.

I imagine some commander decks will finagle their way around this, bouncing/saccing their own Moon-effect generator to cheat around drawbacks of Dark Depths and Lotus Vale and Karoo-lands. But I expect the only difference it'll make in competitive play is that shocks ETB as untapped mountains.

Magus of the moon, drop DD, sacrifice Magus to something. Doable turn 4 easily, 3 with a little finagling (ramp on 2 after sac on 1 or a ritual effect, even a first Rite of Flame will do) allowing another color to fairly trivially bring out Marit Lage. True, it's a little tougher than Solemnity or Vampire Hexmage, in that you need a sac outlet, but I believe there are at least a couple good ones.

I suppose this is why the sucker is banned in modern. When did they do that? I should keep up better.