that's because only certain cards can go on certain champs. they must share the same realm. if you struggle, try playing previous games at higher difficulty. If you are not sure on anything, ask in chat.
I believe there should be a tutorial that involves games vs an AI or something of than nature (similar to the hambo mission). These could come in the the form of a 1v1, 1v1v1v1 and a 3v3. The new players would be allowed to play vs other people. Thus they would have a rough but better understanding of gameplay (Note: the first tutorial would be teaching them how to press the ready button). As an added incentive to have new players (lvl 1’s only), that team could gain an on field advantage, or get an extra weapon drop (in the form of a crate maybe?).
This would encourage higher lvls to maybe consider having new players in the game. An alternative is, for every lvl1 in your starting team, then players in that team get an extra 10 starting and max health. A final option would be to have a team heal 10 (or some other quantity) health every turn that they have a lvl1 alve in their team. Whilst this would make the new player a target, it would involve them in the game, and other players would interact with them more, and give them advice involving how to stay alive as such.
Many people say that there are to many noobs in this game, and i agree. However I believe that the solution is not reducing new players, which would possibly kill the game, but instead educating them into becoming more experienced players.
game: guess the lvl CC will get 2 when i sac all these cards (1*'s=lvl10,2*'s=lvl1or10,lvl3*=lvl8 (souls only)). no coins spent. http://i.imgur.com/RhLtGwN.png
 "Amorphous+"){kind=icon}
 "SeppuKuties"){kind=icon}
 "Magic and Empire"){kind=icon}
 "Bad Eggs Online 2"){kind=icon}
 "Factory Balls 2"){kind=icon}
 "Tyrant"){kind=icon}