I support Landfall in my 360 cube using mostly pre-BFZ cards. it's undergoing refactoring (and will undergo more once we get ZNR) but you can see it at
https://www.cubetutor.com/viewcube/8243
Landfall in my cube is in Naya colors (WGR), the supported color "pairs" (I use a shifted wheel) within that combo are WR and GR, but WG landfall decks are possible (mostly by combining Green Ramp with White Landfall). I took out
Admonition Angel awhile ago (good in my cube, not good for my cube) but you should definitely consider it. White Red is very "landfall aggro" - When Green Red is landsmatter it usually goes a little bigger and tends to be more of a Wildfire deck that sometimes uses Plated Geopede to get in early.
some terms:
"As-fan" - number of cards of interest which you would see in a random pack
"As-Draft" - number of cards of interest which an average seat will see in a full 24 pack draft (77% of the total cards)
here's some numbers to quantify:
* 18 cards have landfall (a third of these are
steppe lynx and
plated geopede at 3 copies each) only
Roil Elemental Ob nixilis, the fallen,
Rampaging Baloths and
Avenger of Zendikar are over 4 CMC.
* 46 other cards reference land somewhere in their rules text (not including actual lands)
* as-fan of 0.75, as-draft of 13.8 (naya specific: 0.54, 10.0)
* I run 20 fetchlands. (4x each of my "allied" pairs)
* I have yet to see the landfall deck get a
Primeval Titan even though there are two in the cube.
* Plated Geopede might as well read "unblockable" for the first ~4 turns of the game
* When the deck isn't competing for its key cards, the resulting deck is the fastest in my format.
Q&A:
1) How many are needed to make landfall aggro work?
18 *Actual* landfall cards has been plenty for me. I put some in every color, but in the core colors I have 12. From experiments with Prowess, "6" cards to make the main is usually enough to make a deck feel like the "Keyword" deck. In an 8 player draft you'll see 77% of the cards in a given seat, so if you were attempt to force this you'd see on average 7.7 landfall cards in WRG specifically in a random draft of my cube. (in reality these are often high picks so it doesn't always come together, which is good.) In my cube this corresponds to an as-fan of 0.75 (3 in 4 packs will contain a landfall card on average).
For comparison, Prowess in m21 is on 7.03 cards in an average draft (a random seat will see 5.4 on average) and has an as-fan of 0.29. (3 in 10 packs will contain a prowess card on average)
I think you could go as low as about 8 total cards that benefit from landfall (that's where my prowess support is). This is close to "is a trap" levels in cube though, especially if the cards are independently good enough to be picked up by people not interested in the archetype.
2) What support cards are good but aren't just useful for landfall triggers:
The first-tier support cards are cards that let you Find more land into your hand (
land tax) play more land each turn (
exploration), or trigger landfall at instant speed (
Harrow).
The second tier support cards are cards that let you repeat your landfall triggers for value
Meloku the Clouded Mirror (there aren't very many of these but check out recently spoiled "Murasa Rootgrazer") or recover lands from your graveyard
Life from the Loam or draw extra cards in general
mentor of the meek
Third tier is something to do with flood like
Faithless Looting or
molten vortex can be a nice support card too, since Landfall Aggro has a tension between "wanting to play as many 1-3 CMC threats as possible" and "wanting to still play 17+ lands". Big mana Sinks like
Fireball or
Kessig Wolf Run are also good for flood.
For aggro shell, the best support is also 'cheap equipment that gives me evasion'
fleetfeather sandals, although if you get to draft the whole pile you'll probably be 'too fast' to want to take time off equipping up, so lategame reach like
lightning bolt, or the previously mentioned
fireball and
Kessig Wolf run might be better. (I found
sword of the animist was too deep.)
In general the best support cards overlap heavily with the kinds of things you are already trying to do with "land" - get more of it into play. In general the second best support cards overlap heavily with other known Red/Green archetypes like Stompy and Wildfires.
3) Is there enough compelling cards to support an aggro *and* a midrange version?
I think the answer is 'probably' yes, but the midrange version was (pre-ZNR) a lot less compelling. (
Akoum Hellkite is just not exciting to me, I'd rather see
scapeshift valakut, the molten pinnacle. I don't think
admonition angel can carry the archetype on its own (maybe there's a UW landfall shell that goes deep on
hedron crab which would work) when AA was in my cube, she either topped the aggro deck and put the last nail in Villain's coffin with khalni heart expedition on turn 6 or so, or was in a super-late game control deck as a repeatable o-ring effect.
This may have gotten better with ZNR, there are a lot more 4-6 drops worth looking at, especially in GW. (which will give us a way to do "midrange lands matter" in Naya that isn't wildfire focused)
Another issue with midrange is that most of the 3-5 drop landfall cards are bad at blocking, so stabilizing against an aggro deck will be pretty hard.
4) is it a good idea to support both decks?
I think it's *possible* to support both decks, but I'd be concerned about too much overlap putting the draft on rails if only one drafter is in the archetype. Moving one of the decks into a different color combo may be smart. (for ex: the cube space I spend on supporting a red green sneak pod deck could be using midrangey stuff like
undergrowth champion akoum hellkite etc.)
the alternative is to go even more in than I did and end up at something like a 1.75 as-fan in all five colors. (which is where original zendikar was). This will make approximately "Every" deck in your cube "a landfall deck, at least a little bit".
prior to ZNR going this deep would require custom cards, but between BFZ, ZNR, and ZEN it seems like it should be possible to make more than one deck of reasonably similar power level in 2+ color pairs using retail cards.