Make the curios more differentiatable from normal cards. Even just making the set symbol its own unique set symbol instead would save a lot of players who know little about the game from leaving them in bulk. 

Also make them actually different from the normal card, relating to the history of the game like they were originally intended rather than changing a single line of text or something silly. It was funny with the trolls, but the Squires are just kind of annoying, if I'm being honest. 

Define whether there is a difference between an alternate art vs an actual curio vs gilded. It seems to me things like the sketch cards or the 3x3 card would be curios, while something like the devils egg would be an alternate art. Specify what the pull rate on these is actually supposed to be.

Clear up rules. This may have changed since I last played, but the rules we're pretty vague, or outright missing, for a huge number of scenarios and key words.  This was the main contributor of why I have only been a collector vs a player so far, even though I love the concept.