Got all the challenges knocked out. It can definitely be done without any of the newer cards. The only card from this generation that floated in and out of use was the cape for +20 HP.
I've never even used the Blaine deck lol. The new cards are cool but none of them feel mandatory compared to the older ones. I still think there are a lot more viable options for decks in this xpac.
+1 for Blaine deck. It's the one I use for doing anything serious (like getting emblems), although that might also be because I don't have two copies of enough cards to build many other meta decks. I've switched one of the Sabrinas for a Cyrus, and there a couple of tools I would like to include, but I'm not really sure what I could drop - might just have to try things out.
I don't use potions, anyway. But the big cape is like a better potion, so it could be useful. X speeds sometimes end up unused, but they can also sometimes be vital. One of the most interesting this with the new cards is that it gives you so many options with supporters and items, but with only 20 cards in a deck, you have to make a choice which to include