yeah i think the card mechanic is important to keep since its all the game is about but giving the player the opportunity to get items allowing him to use shortcuts might be interesting. And i think a mechanic to discard cards might take away some strategy from the deckbuilding part. getting to many expansive cards will make your deck clunky so you have to watch out to prevent that.
Im not a programmer so i used scratch which can be better as most people expect but its nothing you would create a whole payed game in.
Arts are all by me made within the 72 hours so being able to focus on the art part might bring some even better results :)