There's no doubt this game was made to be a unit based, interactive deck style. You make good choices on what units to play, when to block, when to take damage, etc. I'm sure that's what Riot had in mind when designing and balancing initial cards.

Keeping that in mind, this game also has high accessibility. Free cards, cheap cards to cash ratio, direct card purchasing, free game, all of those good things. However, this means its a high influx of peak power/meta decks (Which players will 100% do almost all of the time).

So with high accessibility, and high playercount, there are going to be decks that are played a sizeable portion of the time more than others unless kept in check. Unlike Hearthstone or Artefact, or MTG, there is no cost gate to constructing a deck really. There's nothing stopping players from just building one of the top decks and running it, which is a good and a bad thing. It's good because players can come in and play what they want without much of a time or monetary commitment.

But here's why its bad.

Decks are effective when they pierce the current meta and undermine the meta and structural formula. Almost all of the cancerous top decks we've seen so far have had one goal in mind: Consistent play, consistent wins, with the least amount of interaction possible.

Elusive burn: Play an assload of unblockable units and bandaid your weakness to where you don't have to care much about your opponents plays.

Heimerdinger control: Play an assload of removal to stop your opponent from advancing while building your own boardstate for free with Heimerdinger

Ezreal control: Stop your opponent from ever hitting you then pull out 20 damage in 2 turns in direct damage and burst cards that you really can't avoid.

Fearsome Frostbite: (Even I'm guilty of this deck) Fearsome unblockable, using frostbite to deny trades or deny blocks alltogether.

Frostbite Overwhelm: Deny favorable blocks and do as much nexus damage as possible regardless of blocks

Ionia Control: Prevent your opponent from doing literally anything

Players are 100% going to aim to subvert the formula you have presented to them because that's how decks become effective. The main problem I see with the game so far is there are too many tools to prevent interaction, and too many cards that abuse that fact to win. I personally think Zed is one of the most broken cards in the game, yet still he is an interactive card, and doesn't stop me or the opponent from playing other cards. Each deck was designed to run cards to strengthen your own deck, and cards to stop your opponent, but the deckbuilding has almost entirely become running 1 main 12 card package and the rest is stopping interaction.

Almost all of the top decks main focus is to make your opponents choices matter the least amount as possible. It's toxic deck design for both players. Riot needs to be on top of balancing nearly WEEKLY before the game is released, as if left unchecked or keeping the current pace of balance it's just going to become a match of "Who draws best" and the game will be dead before release. The game is very accessible but no one wants to play a game where literally nothing they do matters because that's what all the top decks try to do, minimizing the impact of your choices.

Personally, I think making some untargetable keywords and slapping it on some units is a fantastic way to mitigate it. Tech cards become meta influencing when they start to play into the majority of decks.