With Diffusion Sliver, you get to counter a spell or ability an opponent controls that targets a Sliver unless its controller pays 2 colorless mana. These abilities stack as well, meaning if you have two copies of Diffusion Sliver, an opponent has to pay 4 mana. In Modern, this wouldn’t get around Abrupt Decay (which is also still in Standard until October 2014), but overall this card is a great way to protect your key Slivers from being targeted by removal. It’s one of the best of the bunch by far, and definitely Constructed playable.
“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.
However, this effect actually did exist on a previous Sliver: Two-Headed Sliver, which cost one mana less at 1R. The difference is that prior to the Magic 2014 re-imagining of Slivers, all Slivers affected all Slivers on the board. That was a common from Time Spiral, so for Modern purposes, that card is actually better unless you’re in a Slivers mirror-match – which is not incredibly common in the Modern meta-game. It’s probably worth running in Standard, though.
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.
Magic 2014 had a bunch of Slivers, too. So when these Magic 2015 slivers arrived, Slivers would appear to be a playable deck in Standard. There was 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 had 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 had 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 was some potential for Slivers to make some noise. But after the arrival of the Khans of Tarkir block, these few Slivers became a curiosity in Standard. Most of these Slivers are quite Modern-playable, though. 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 Magic 2015 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: Magic 2015's Slivers are good. They made only a slight impact in Standard, though, with a very limited window in which to actually provide much value. But these few Slivers definitely gave deck builders in Modern and other formats more ammo to play with.