I doubt that you will get new players to join with the current battle matching system. It's seriously flawed. Skill is irrelevant as you will always lose to a bot with more power. It makes playing at low levels boring and a waste of time. You might get them to fork out the initial $10 but they will drop out quickly once they have frustratingly tried renting andget pounded in bronze by a neverending series of tofus, lorcuses, dragons and maxed out bots.
battle matching needs to be based on owned/rented/delegated power. Basic maths dictates that when two players of equal skill fight each other the person with the most power will always win.
Also you want manual players at higher levels otherwise it will just be a few of you with just a bigger number of bots. You might as well circle jerk.
Frustating, but not that bad as you claim, I made it to Silver 2 relying on foundation cards. Upgrading Conclave arcaana rare summoner to level 4 , I assume, I can reach Gold 3 too.
Basic logic dictates when there are two players of equal skill the person with greatest power will always win. End of.
I'm interested why you think that after forking out $10 and getting owned by bots using legendaries a new player would think "I know, I will fork out a significant amount of cash for some rares".