Hmmm… Define ‘you’ — because that other… player seems to be always drawing theirs. 
My personal rigging theory [1], [2] 
has been that the game might use advanced AI to gauge your IQ/ICQ (anyone remember that ‘meme’?)/‘skill’ (or at least ‘accuracy’, like a chess engine could)/etc, then adjust your draws accordingly to ensure some ‘paraintellectual’ help for the less… ‘privileged’ 
playah in order to enforce ‘ekwolity’ and make the game more appealing for the masses… But I’m repeating myself a lot here (see the references above), am I not?
As for tracking your ‘win rate’ with particular cards — interesting idea, but I’m not sure it’d be that effective or as good as you think, especially considering both high… variance 
happening in this game and statistical errors. However, the technology to do this kind of ‘rigging’ is already in this game, I suppose I gotta self-cite:
Disclaimer: yeah, it’s hard to verify this theory, unless someone leaks the server code or something, so you might call it a ‘conspiracy theory’, rather than a scientific one. However, lemme note that just because something is a ‘conspiracy theory’, it doesn’t mean that it’s not true — or there is no conspiracy. After all, Snowden, for instance, only documentally confirmed what many have long suspected.
Yeah, you should have done a better job, obviously. 
PS About ‘win rate’ of particular cards — one more point on why you’ve gotta explain the meaning of it to me first. Consider a card so ‘overpowered’ that it’s played in virtually every deck (pre-nerf Astalor would quialify, I guess?). What do you think its ‘win rate’ would be, then? That’s right, approaching 50%, which is the exact number for the ideal case of being played in all decks exactly. This is just an illustration why you can’t interpret an abstract number like this naively.