Attracting new players is definitely important but so is maintaining a sustainable economy so the game can continue.
I'm looking at your account and it is mainly bronze level cards and in the current environment with the current rating system you did Champion 3, though mostly by beating other bronze or silver level accounts.
There will definitely be an adjustment period and this change will be a reality check for players who have gotten used to reaching leagues that are much higher than the level of their cards. Hopefully people will understand why Collection Power was needed and they will see that the competitiveness of the lower leagues will increase when players are battling decks that are at the same level. The reward structure will also change (especially with multiple leaderboards and prizes for each) so I definitely think there will still be opportunities for new players.
RE: New Reward Cards & Collection Power Update