I’m a patient person, so no worries from my end.
Having a way to discard cards for hand management with a persistent hand of cards would seem to be pretty important for a story designed around the concept. I wouldn’t worry about making cards unplayable (especially for some things which are mutually exclusive) because the game state (with good design) could return to a point were they become playable again. The player question is whether to continue to hold onto it for that possibility or to discard them to make room for something useful in the short term. I’ll think some more about this at any rate.
The <<addcard>> trick for time separated content is an interesting design choice. Progress qualities is something Fallen London was using but I would agree that inserting new content is more difficult with them being pre-numbered like that. Adding parallel content is easy, because they would share the same requirements, but you’d have to find and edit the whole chain to insert something inbetween after the fact. Arrows in the editor would indeed be cool.