A heavy base color plus a light to medium-sized splash of a support color is actually one of the most attractive options that you can find, especially in color-intensive formats such as Zendikar and the upcoming Zendikar / Worldwake.
In order to support cards with heavy color requirements, you need a lot of lands of a specific color. And I'm not talking an even split of eight or nine lands between each of two colors; I'm talking a minimum of ten lands to get the most out of your cards.
A Kor Aeronaut becomes significantly better when you can reliably cast it on turn two. A Gatekeeper of Malakir goes from being borderline unplayable in a deck with six or seven Swamps to being absolutely awesome if you have twelve plus black producing lands.
If you are anticipating that you will run twelve or more Plains, Kor Aeronaut is a first-pickable card. If your deck is shaping up to have six or seven Plains, then you probably won't want to pick up that Kor Aeronaut until about the middle of the pack. If you think you're going to run eight or nine Plains, Kor Aeronaut will remain a fairly early pick, but it won't be one that you are particularly happy about making. The thing is, Kor Aeronaut is only better than Wind Drake if you can actually cast it on turn two. If you can't run out your Kor Aeronaut on turn two, it will still be fine—a 2/2 flyer is nothing to scoff at—but it won't be at all special.
Being able to fully utilize your cards is immensely important in any format. But, because Zendikar is such a fast format, it's even more important than normal to be able to cast your spells in a timely manner. If you're on the draw and you can't cast any spells until turn three, you're usually going to be pretty far behind. If you don't have a play until turn four on the draw, you might already be out of the game.
Similarly, you lose so much equity if you can't take advantage of your opponents' slow draws. A good number of games in Zendikar Limited, and no doubt Zendikar / Worldwake Limited, can be essentially over within the first few turns. If you have trouble casting your spells, it'll be pretty hard for you to win by take advantage of your opponents getting slow starts and easy to lose when your opponents come busting out of the gates.
This is relevant for both color-intensive and non-color-intensive cards alike. You get a noticeable amount of value out of being able to pretty much always cast your two-drop on turn two, and out of not being forced to mulligan hands just because they are missing a color of mana.
Given how many of the top cards in Zendikar and now Worldwake require a lot of mana symbols (I'm looking at you, Leatherback Baloth) you are often going to want to try to weight your Draft and Sealed decks towards a single color. This will allow your deck, more often than not, to actually cast its spells when it's supposed to.Click to see the full Visual Spoiler.
If you think you can build your Sealed or Draft deck without too many color-intensive cards, then you might be fine running a 9–9 or 10–8 mana base. But be careful. Some cards in Worldwake are more color-intensive than you might think.
Even some cards that might look like they can go into any deck, are actually only attractive in decks that have a ton of lands of the appropriate color. For example, I have been told that all but three of the multikicker cards in Worldwake (all three of which are already in the Visual Spoiler) have colored mana costs in their kicker costs. This means that a huge majority of the multikicker cards—and all of the common ones—are more color-intensive than they might appear at first glance.
Let's take a look at Skitter of Lizards. How many Mountains do you think you would need in your deck for Skitter of Lizards to be good for you?
I'll let you know right now, it's probably more than you think.
You actually need at least ten or eleven Mountains for Skitter of Lizards to be an attractive option for your deck. Sure, Skitter of Lizards will still be playable with eight or nine Mountains, but it really doesn't become something worth playing unless you've got a double-digit number of red sources.
Reasonably fast mana fixing like Harrow can act as land substitutes for a card like Skitter of Lizards or Kor Aeronaut, but slower mana fixers like Khalni Heart Expedition or Frontier Guide cannot. Unless you can reliably cast Skitter of Lizards as a 2/2 for three and a 3/3 for five, it's just not going to do much for you. Do you really want to be playing a card that you often won't be able to play as a 2/2 until after turn three, or a 3/3 until after turn six?
Instead of looking to play decks with 10–8 or 9–9 mana bases as you often would in a format with less intense color requirements, you are going to want the majority of your Zendikar and Zendikar / Worldwake decks to have 12–6 or 13–5 mana bases.
So when you sit down to build your Sealed Deck at the Worldwake Prerelease this weekend, you shouldn't simply look to put together your 22 best cards in two colors, add 18 lands, and call it a day. You should instead look to see if you can build a deck which is weighted heavily in favor of one color, even if it looks like you have to play a set of cards that are weaker to do so.
Similarly, next time you sit down for a draft. Instead of looking to draft only the best cards in your two colors, you should try to focus on drafting a base color and then expand out from there.
I'll have more on drafting a base color after Worldwake has been out for a bit.
While there were no gold cards in Zendikar, some color combinations were without a doubt more popular than others. Green-blue landfall, red-white beatdown, black-red beatdown, blue-red tempo, and black-green control have all tended to get a good amount of play during the last four months.
But aside from some synergies between colors, there were no cards that actually required you to play a specific second color in order to reach their full potential.
I know that some cards, like Windrider Eel, might seem like they need to be paired with, say, green to fully utilize their landfall triggers. But in actuality, I'm often just as happy, if not happier, to have Windrider Eel in my fast blue-red deck as I am in my more controlling blue-green deck.
Worldwake, on the other hand, has a cycle of cards that go from being decent to being very first-pickable depending on whether or not you are playing the appropriate colors.
Sejiri Merfolk is a completely playable card in any deck with Islands. A vanilla 2/1 for two, while not particularly special, is still a fine way to fill out your curve.
Because Sejiri Merfolk isn't very exciting for players without Plains in their decks, you're likely to have a good number of shots at it if you're playing white-blue. However, unlike an actual gold card, Sejiri Merfolk doesn't actually require you to have a bunch of Plains in your deck.
Sure, Sejiri Merfolk has a lot in common with gold cards, but there are some distinct differences. While you would need at a bunch of blue and white sources to want to play a card like Deft Duelist, Sejiri Merfolk doesn't have any sort of white mana requirement.
That means that you can be playing a base blue deck with a light side of white and still get pretty much full value out of your Sejiri Merfolk. Twelve Islands and six Plains or even fourteen Islands and four Plains would be fine. If you are planning on playing twelve Plains and six Islands, Sejiri Merfolk will still be quite good, though not quite as strong as it would have been with an extra Island or two. Once you're looking at playing five or fewer Islands, however, Sejiri Merfolk might not be a good fit for your deck.
Sejiri Merfolk is part of a cycle of uncommon creatures that are all quite reasonable whenever you can cast them, but become extremely powerful when you have their supplementary land type.
While the Sejiri Merfolk cycle alone isn't quite enough to incentivize you to pursue an allied color pair from the get go in a Zendikar / Zendikar / Worldwake draft. Having the opportunity to see one (or more) of these powerful uncommons in the third pack can certainly act as a tiebreaker if you're on the fence, trying to decide between pursuing an allied or non-allied color pair.
Once you've played a set a few times, you begin to get a sense of what tricks your opponents could be luring you into. But at the Prerelease, you don't have the luxury of that experience to help inform you of what your opponent is trying to set you up for.
While not too many tricks have been spoiled at the time of my writing this, one particularly devastating instant has been made public: Join the Ranks.
Join the Ranks can be an absolute beating even if you do see it coming. If your opponent has multiple Allies with relevant abilities, you're going to be hurting even if you do try to play around Join the Ranks. But if you aren't aware of Join the Ranks, you could get thrashed in ways that you will remember for weeks to come.
So if your opponent gets into a funny-looking combat situation with an Ally, Join the Ranks should be the first thing that comes to your mind.
Have fun at the Prerelease!