That's pretty much it...still trying to win a second game at normal. After 50 games challenge won't advance so I decided to start a new character. (Especially since the bugs deleted my high level toons anyway)

Well customize deck no longer does anything.

All it does is show the same starter...period. No options to show all other basic cards available. 

 

Help please. 

You can Edit deck for new characters in the new croup. Only before the first scenario.

Deck customization only did "something" before starting your story, as Hannibal said, or when you end up with less cards than you can hold (banished more weapons than you acquired, cards otherwise removed). You are then forced to pick card(s) to fill up to your card type limit for those characters (it is said that you can pick all base + treasure cards for up to your AD - 2, i.e. after banishing an ally in AD6 scenario, you will be able to pick up new allies from both base set and treasure cards from AD1 to AD4).

 

Otherwise, the deck customization is there if you want to move cards around your characters in between scenarios.

I have also run into this in Quest mode. It used to be that for a new character you could customise their deck with cards from the base set before playing the first game, but this no longer appears to be the case.

Did you try add only new character / characters? Not any experienced.

I will add that I just started three new characters in quest mode (all three the new character alternates) and could not figure out how to change the initial deck.  I have done it numerous times in story, but quest wouldn't go.

On the screen where you select difficulty level in Quest mode, go to "Manage Decks" button and you should be able to customize any non-experienced characters deck. I have had no problems with this.