It's pretty easy of you got the luck to get all the good cards, I've been playing since the last light panzer rotation and even started a second account and have only been checking Guildshop, doing arena, clearing maps for gem recruits, happy weekend, whenever I have time. True I am only lvl73 and 64 but I can't find any joy when I can't afford to spend money on cards as they are currently priced, so I do my best as f2p and can say after all these months only one hp card showed up when I started my second account and I did not even have time to run the mines for the first time yet then. This is a game based on luck, there is no easy and hard difficulty about it ATM, it's you got the cards or you don't. I'm in the don't category and don't quite understand my addiction to this game, maybe it's the nice art, the widely varying community, or that I just have hope that this game will become better at some point and I'll be here for that.
They really need to buff or reduce the cp cost on some cards( Flesh Lotus QUEEN for example) because there needs to be some sort of balance between all the cards, not based on what looks good for "variety". I have been told Flq is cp inefficient simply because it adds "variety".