Hmmm, I think you are assuming players got to Gold with level 1 cards. Do you have proof?
I'm more thinking they get there with decent cards and then send those cards to another account and level that account up before end of season.

Regardless of how they got there, your solution only solves the problem for level 1 teams. If I was a bot owner I'd just increase the levels of my bots.

Your idea, is only valid for today's problem and not a solution for tomorrow. Sorry.