The issue with DOTA is that its audience is self-limiting. You're locking 5 strangers together in an hour long game where failure is heavily, heavily punished and you're penalized for leaving early.
Where are the games for those of us who loved Half-Life and Portal? The last thing I want to do at the end of a long day is be yelled at by college kids and teenagers for an hour.
I can't speak to the F2P card game because it does not exist yet.