Any company that has a product built on recurring payments will always tend towards becoming predatory in the money they need to extract because #1 they need to have pinch points to ensure they get money at regular, predictable intervals since they're a business and #2 because there is absolutely no reason for them not to turn the dial up on the micro-transactions -- up and up -- slowly until the profit gained is cancelled out by the quitting players.
Yeah, as a former legend/somewhat competitive f2p player, it's either spend money or spend time grinding arena/dailies for gold/dust (what I did) to be able to build all the meta decks and useful tech cards. Although to be fair, if you're just going for a decently high rank and not aiming to compete in tournaments, you really only need one top tier meta deck but even then that could require a hefty amount of resources to craft.