Account gains are made during regular season and for many players, lost at the end. People have a tendency to get attached to the rewards their MMR is eligible for. This attachment seems to create frustration. But if we look at the numbers it's often a net loss.

I expect the new set to allow many players to own a ton of new, useful cards without the sizable investment required now. They just need to hold on to those cards instead of selling them for rental fees :). Sitting in S3 for the daily seems ideal for leaner accounts. Provides an extra daily loot chest and doesn't scale as hard on CP requirement as every proceeding league.