You should look at Heroic Intervention as a way to protect your board when you use MLD.

Don't give up on W6 it's extremely powerful and copies can be found cheap. I picked up my copy recently for 30$.

I'm also surprised you're not running Scapeshift

I play a landfall version of windgrace but I'm focused on valakut/urborg combos - https://tappedout.net/mtg-decks/a-love-letter-to-the-urborg-forest/

Heroic Intervention is always something I think about adding when I'm not working on the deck, and forget about when I am working on it.

I'm not big on the scapeshift plan for the deck. It is certainly one way to take it, but it doesn't really inspire me and the odds are low it actually wipes the table, even if you have an obnixilis. I would rather focus on my main strategy (MLD/Borborygmos combo post sideboard) and then have 1 back up strategy, the landfall one, than try to divide the deck focus and add a third scapeshift strategy.

I'm also working on improving the removal package for this deck. I swapped Sylvan Safekeeper for Decree of annihilation, and am looking for a card to replace Zuran orb.

Decree of Pain*

Zendikar Rising spoilers has started, and in the tradition of all Zendikar sets, it's time to reevaluate the lands matter decks.

Some updates: Zuran Orb out for Exploration. Decree of Pain out for Toxic Deluge. Bringing in a Heroic Intervention as well, in place of Price of Glory. I want some more interaction. Deflecting Swat is something I am currently very interested in. The new blue enchantment means I need to add a lot more enchantment hate. I am probably going to cut Mina and Denn, Wildborn for an Oracle of Mul Daya.

I am looking to revamp the mana base some. Cut cards like Rootbound Crag and Karplusan Forest for more basics. I'm gonna add some snow basics, and also cut one of my 3 mana ramp spells for an Into the North.

Comments about the new cards:

The new landfall extra combats is powerful but not what this deck is looking to do. I don't have many creatures, and most of the attacking ones are already heavy at the top end.

I am in love with the new double faced cards that are spells/lands. However, most aren't what I'm looking for. I am extremely happy to add these to my other decks, especially those with Karoos/Ravnica bounce lands, but I don't have those in this deck. The red mythic might go into this deck, as an untapped land and potential removal spell, but I haven't decided.

The new not-Avenger of Zendikar is interesting. I need to go more basic heavy for it, which I am already working on revamping the mana base. I have found myself a bit light on blockers recently, so another effect like this is not bad.

I am kind of surprised to say it, but so far my lands matter deck might not get much from a Zendikar set. Obviously the set isn't spoiled yet, and I fully expect a green mythic flip land will find it's way here.