Hearthstone has a troubled history with silence effects. In the game silence removes all buffs, debuffs, and abilities of any kind, reducing the minion it targets to its base stats. This is a difficult mechanic to balance correctly because it varies so wildly in power. Right now silence effects are being run in a huge number of decks because there are a variety of really powerful cards that are absolutely ruined by silence. While any kind of play needs some sort of counterplay I feel at the moment that silence effects are too good and are making the game worse.
One of the really fun things in Hearthstone is to try to make enormous minions with crazy abilities. People really like trying to pull off their crazy thing but when they do it is regularly met with a silence effect that ends all the fun. As an example, consider Carnivorous Cube:
This card is hilarious thematically, and really powerful. You can bash your minion into an enemy, leaving it at 1 health, then eat it with the cube. When the two new copies pop out, they are at full health! That is a huge swing. The problem is that when you try to do this the fun police show up and silence your cube, preventing the minion you killed from being spawned. This massive loss of tempo is often game losing, so nobody uses the cube.
Except warlocks. They use the cube. Do you know why?
Two years ago we had a similar situation going on. People were running Ironbeak Owl in way too many decks because it was a cheap 2/1 minion for 2 mana that silenced an enemy minion. Blizzard didn't like how prevalent it was and how much it suppressed the fun and wacky stuff people wanted to do. They nerfed Ironbeak Owl to cost 3 mana instead, and it hasn't been seen since. At the time it was clear what the natural successor to Ironbeak Owl was - Spellbreaker.
Spellbreaker is 1 more mana for +2/+2 in stats, and is the new standard for silencing things. In fact we see two copies of Spellbreaker in all kinds of decks, ready to be the fun police for anyone trying anything too entertaining. Spellbreaker needs a nerf. Not because it is especially overpowered, but because the fact that it gets run a lot just eliminates all kinds of fun and interesting stuff from the metagame. You can't play a Lynessa Sunsorrow deck in any environment where there is a lot of silence, and I want Lynessa Sunsorrow to be good, dammit!
Lynessa isn't overpowered. If you let people run all kinds of buff spells then she becomes a really powerful but vulnerable finisher. She can still be killed by all kinds of single target removal, but at least that means people are running single target removal to stop big threats like her. When she just gets demolished as a side effect of people running Spellbreaker for other reasons entirely that is a sad state of affairs.
Hearthstone is more fun when people get to try their big exciting things and get paid off. If you want to avoid getting demolished by gigantic scary stuff then run cards like Assassinate or Deadly Shot. I don't mind the silence cards that belong to classes like Hex, Polymorph, and Silence - at least those are deliberate choices that only some decks can use. What I don't like is masses of silence effects out there raining on the parades of people wanting to play minions that aren't just big piles of stats.
I say this even though right now I am running Spell Hunter and silence effects are pretty much worthless against me. Hell, I want every opponent to be running as much of it as possible so I can laugh at them. But I do want a metagame where I can run Carnivorous Cube or Lynessa and have them be effective without me having to kill my own stuff right away. I think Blizzard is going to come to the same conclusion and nerf Spellbreaker, most likely by increasing its mana cost to 5. Good riddance.
(Yeah, yeah, aggro decks need Spellbreaker to cope with turn 6 Void Lord. The problem in that scenario is Void Lord, so that may need to get addressed on its own.)