There are quite many new comers who played no or very few games and left for good. Some reasons:
(1) I have no idea how to start. No starter deck. I spend hours to build a decent deck to play my first game. I don't use the "randomize" button because it is very likely to give me a rubbish deck. A page to explain how this system works (challenge -> accept challenge -> go to game page...) would be great.
(2) I don't know how to play better. Newbies, especially those who haven't played card game before, will feel lost. They don't know how to build a better deck, how to master the game. They will be frustrated and leave after a row of losses. Apart from game manual, a page for game tips/tactics/skills would be great.