There have always been broken cards since the beginning of the game, as simple as that.
I remember a lot of "old school" cards that made the matches super infuriating, because it left you with little to no counter-play.
Here are some examples of what I'm talking about:
-Flamenco Zombie (up to 8 face damage)
-Zombie Coach (up to 4 invulnerable zombies)
-Walrus Rider (it was hard to counter amphibious zombies back then)
-Mirror Nut (high damage - high defense deck)
-Grapes of Wrath (free 6 face damage)
-Dandy Lion King (up to 10 face damage)
-Re-Peat Moss (One-Turn-Kill combos)
-Potted Powerhouse (same, but with Plant Food)
-Admiral Navy Bean (free face damage)
-Winter Squash (kill any zombie)
The card that I used to hate the most out of all was Grapes of Wrath.
If you left it unattended, it would kill you.
If you killed it, you would take 6 damage.
I mean, you could literally win a game with just 4 Grapes of Wrath and some control cards (removal, healing).
But, if this cards used to be so OP... Why they don't have much play anymore then?
The fact here relies on 2 things: Counter cards and learning how to play around them.
From time to time the devs analyze the cards that have the biggest win-rate and release some "counter-cards" to them. (Bonus Track Buckethead to counter Bonus attacks, Sneezing Zombie to counter Healing, Three-nut to counter Weed Spray, etc).
What I'm trying to say is that, I don't doubt that Going Viral or Untrickable are causing a lot of trouble right now, but sadly these cards are here to stay. That's how the card variety works. The devs want a card that gives Zombies frenzy, so the game will get a card that gives Zombies frenzy. However, this doesn't mean that the game is over. Players will adapt to the broken strategies until A) The card gets nerfed, B) they release a pretty good counter-card or C) they get so good at playing around the card that it is not playable anymore (Anyone remember Bad Moon Rising?)
So fear not my friend, there is still hope. Wing Nuts, Zucchini, Briar Rose, Splash Damage or simply just aggressive decks are good counters for these cards right not.