“It has been mentioned by some players that Thorncaster Sliver is already in Standard and does pretty much the same job as Leeching Sliver, and in fact, is able to make Slivers deal damage to creatures as well. However, Thorncaster Sliver is 5 mana. Leeching Sliver is two mana, and their abilities stack as separate instances. So Leeching Sliver is overall a far more aggressive card and even though it’s only a 1/1, Thorncaster is merely a 2/2.”
I definitely like this card over the Thorncaster Sliver. As a two-drop, it may be fairly easy to remove, but it also is going to help deal its fair share of damage before it’s gone.
That being said, making all Slivers you control indestructible is huge, especially in a Slivers mirror match-up – unlikely, but possible. Being able to survive most board-wipes definitely helps your cause. He’s also currently the least expensive of all of the Sliver Legendaries (at this time). He is definitely a potential Commander, but his best place is in Constructed.
Modern already has Cavern of Souls and Ancient Ziggurat to help cast Slivers, but having yet another play-set of a land that fixes mana for any of your Slivers very much helps. In Standard, Sliver Hive and Mana Confluence is all you really have. The fact that it also can tap for 1 colorless mana is a nice bonus, and the third ability to create a 1/1 colorless Sliver creature token for 5 mana is just a nice little bonus you can use as a mana sink (as long as you control a Sliver, that is.) It’s a very strong non-basic land, even though its usage is so narrow.
So the problem right now is that Magic 2014 has a bunch of Slivers, too. Right now, Slivers would appear to be a playable deck with Galerider Sliver at a single Blue mana able to give all of your Slivers flying and Manaweft Sliver at 1G to help all your Slivers become five-color mana rocks. You also have Predatory Sliver at 1G to give all of your Slivers +1/+1 and Blur Sliver to give all of your Slivers haste. To top it all off, you have Bonescythe Sliver at 3W to give all of your Slivers double strike. All things considered, you could have an extremely nasty Sliver list. You even have Obelisk of Urd in Magic 2015 to help with Tribal! It’s 6 mana but it has Convoke and gives all creatures of the chosen type you control +2/+2.
So are the Slivers good in Magic 2015? I would say that Constricting Sliver is only Commander playable, and Two-Headed Sliver may be a bit better than Belligerent Sliver in Modern. Until October 2014, there is some potential for Slivers to make some noise. But unless the Khans of Tarkir block has more Slivers, they are going to be a curiosity for awhile. Most of these Slivers are quite Modern-playable, though, and they have all definitely strengthened Slivers in the Commander format. Five of them are also uncommon, which makes them easier to get, and the Hive is only a rare in a Core Set.
I like that Wizards put these new Slivers into the M15 Core Set, but it felt like a plant for Casual Constructed more than anything else. Slivers are not really a viable draft strategy in M15 Limited because there simply aren’t enough of them and there aren’t any at common. I do like all of the Slivers overall, however, and I’m excited to see them potentially start showing up in Modern on a more competitive basis. I love the tribe, and I wish they would bring back their original “hive-mind” flavor of affecting all Slivers, but I’ll live with these. After all, it’s always better when you get to enjoy the effects and not your opponents.
Final verdict: M15 Slivers are good. We’ll just need more in the Tarkir block for them to have much impact in Standard. But Modern needs to watch out: they have some new ammunition to play with.