I think the collection score will be pretty bad for the new comers.
The most fun part of the game for me is to try doing the best with limited level of cards. The is always a fun part of the free to play game: try to go as far as you can without buying too much power-up. I have quite low deck value but I usually always reach the diamond II league.
I don't think it is an issue to let people with low level card reach high league. It means the game leave enough rooms for skills.
I think the collection score will make the game less skill focus and more cash/investment focus.
I think some rules against multi accounts would be more productive.