Unfortunately, in addition: for to each person we lost from cpc, we lost 100 from bad new user experience. Also, I think with a little hard work and some luck I can convince a good amount of those who left for cpc to give us another shot, but the users who left from a "bad new user experience" are gone for good.
The "content" of "cost per content" is a pretty good example of an ecosystem problem. Right now, the game's only "content" is "cards", "playable decks", "Events" and "other players." Tournaments are too infrequent to count, really. Events run hot and cold and require a lot of man-hours for such a temporary gain. Improving the amount of "other players" is more of a result than cause, that will go up if other things get better. "Playable decks" is the content that matters most in reality. The number available at the top-top tier varies a little bit based on balance, but usually playable just means strong files that get reasonable wins, like Martial Artists, Undead, and the pre-builts. These have two ecosystem challenges: first, based on what data I have, it seems users are not motivated by playable files, at least in terms of spending. They are motivated by cards, which is not the same thing (meaning someone would mostly want a single (unusable alone) copy of Dio then an entire, fully playable monster file). The second is that most average players have zero motivation to have more than one playable file at a time (although they might be interested in upgrading their present one some how, or replacing it if it becomes obsolete). Ecosystem changes can help this. For example, LoL handles this by periodically releasing OP units that are susceptible to a specific strategy (to promote using it). This way, it's good to have at least one unit for each of the major strategies. Underdogs and Achievements also helps this, but they need tighter integration. Some games (including Altiel 2, strangely) have daily events that ban certain units, again to make it good to have a secondary or tertiary playable file. Anyway, there are lots of ways to deal with it, but we can't forget that even CPC is part of a larger ecosystem.
For a game people have spent anywhere near as much as they have on, there --generally speaking-- needs to be dozens of interesting, compelling things to do in the game all the time. And that's a better ecosystem-wide definition of content.
"Scissors are overpowered. Rock is fine." -Paper