Instead of bringing out new events maybe you should think about balancing, or at least allowing for some counterplay to some of the legendary/mystic cards already released.
There is zero counter to Hellfiend.
The only counter to Firewitch is a split second spell. Which means in order to counter her you must have a quick spell as one of the two spells.
Nature Guardian can only be countered by some spells or by Silver Archer or Lord Sumrak. Maybe if you’re lucky you can drop 2-3 melee units right in front of it, but if you can’t, there’s no chance to hit it.
Lord Sumrak is countered by another Lord Sumrak, or the next five units you play leaving the other two lanes undefended.
Does Bloodstalker have to have such high speed? Maybe the speed should be inversely proportional to the boost it gets.
Why doesn’t Reflector reflect Revenant’s attack??? At least that would offer something as a counter to a high mana Revenant.
The other legendaries have counters.
Have you seen what Rolling Rocks do to Immortal Knight?
Anything vs. Rune Cannon.
Trinity is a waste.
Soul Leech is countered by range and by not killing the other units.
Mana Wraith. I love when the opponent plays this extra slow card. I know that all the other cards they have from now until Mana Wraith is destroyed costs more, so I wait as long as I can before I kill a Mana Wraith.
Phase Assassin is great against single opponents but useless against several.
Punsiher might be great early but higher cost ranged cards as well as hordes chew him up.
And before any of you come back with “but they’re legendaries, they should be powerful”, think about how Clash Royale handles Legendaries. None of them don’t have a counter or several options to counter.
I hope you keep track of card win rates, especially the win rates of decks that have one of the overpowered cards vs. decks that don’t.