I believe that a great idea for this game would be a risk free way of playing. You can create/ use existing deck and everything would be maxed level. This could be a way of testing new u it’s to see if we want them or if we think they are worth grinding for(I personally don’t like any of the legends of this season). As I said already maxed unit should be a must so it doesn’t become lv 17 vs lv 5 troops. A requirement of level 20 or so brand new players don’t fight or brand new right brand new as us golds-champions can fight to learn new strats. I believe it would be a fun way to test decks and not have to worry about ranks.
On the other topic more deck options sound great but I know that is a huge Hassle with boss blitz and campaign. Maybe in this new feature we could copy/paste decks if we have all the units and are all from one faction. That way there are less bugs(maybe) and it is solving 2 birds with 1 stone.