So the first card for Battle for Zendikar has arrived: Oblivion Sower.
There are a few interesting things about this card for me and most of them aren't very exciting.
First, I think the ability on Oblivion Sower is likely the new Eldrazi ability. Of Return of the Eldrazi's colorless Eldrazi creatures, all of them had Annihilator. Which means that the ability of 'exile the top X of an opponent's library and then get Y', where Y = creatures, lands, spells, whatever, is probably the ability of all the new colorless Eldrazi.
I'll just use Eldrazi as short for the colorless creatures from here out. Nobody cares that Rapacious One is an Eldrazi.
I don't think this ability is very exciting, myself and I think it's got a similar problem to Annihilator, which has been nixed as a mechanic for being too 'feel bad'. In the same vein, I think that the free theft of people's decks also feels bad. I think of a card like Shared Fate, which denies people the ability to play their own decks and I see a cousin to this new Eldrazi mechanic.
They don't print cards like Shared Fate often and for a good reason: it's complicated and it cuts a player off from their own creation.
There's also a feel bad if Oblivion Sower misses. Sure, you're likely to get at least one land out of the deal, and just dicking around with the top four cards of various decks I own suggests that two lands is going to be average--and that doesn't suck! But. You're going to miss, too, leaving you with a 5/8 that has no other abilities.
It could be even more one-dimensional; the Eldrazi could only steal lands. That would avoid the 'feel bad' of cutting someone's deck off, but my goodness is that boring as hell. Plus, it would mean that WotC is avoiding a big chunk of design space and I'm not certain why they'd do that. I may not like this ability but the variance of stealing spells or permanents makes sense, provides an actual threat and still allows for the ability to miss. Leaving players with giant vanilla creatures.
Avoiding these feel bad moments means that my next point is pretty likely.
Since the ability on Oblivion Sower reads 'put any number of land cards that player owns in exile' suggests two things: a) that this block will put things into Exile more than Magic has before and b) that this block will interact with that Exile zone more than the game has before.
Making the Exile zone Graveyard 2: Electric Boogaloo. I've talked about this before and stonethorn rightly pointed out that the Exile zone has had a steady stream of cards interacting with that zone for a long time. They are always limited in their interactions but they do exist. My problem is that Exile zone interactions adds complication to the game and I don't think the game needs to be more complicated.
Now, on the other hand I recognize that while it may've been more interesting to have those cards go to the graveyard instead, it presents other problems, because if the Eldrazi milled decks and then stole, players would have more challenging decisions to make playing decks that are using the Delve (in Standard) and feed the graveyard at large (in all other formats). That seems a lot cooler however, I do see that there's an inherent risk powering up your opponent's strategies and leaving you with a vanilla 5/8. That kind of risk makes for an interesting game--or it might, if you didn't pay 6 mana for a 5/8 that has no other value if it misses.
This takes away from the coolness and the threat that the Eldrazi represent, bringing me to the last point.
I just don't get the same feeling from this mechanic as I did from Annihilator. Annihilator felt scary and new, alien and different from the other colors. This just seems Blue, attached to a body that dies to Terror.
That doesn't mean that I think that every Eldrazi should be Emrakul. That would be awful for the game and I don't believe that Oblivion Sower has zero impact. It almost certainly needs more context to be properly evaluated. But it doesn't bring that same sense of dread, either and that's too bad.