The 100 burn cards thing is great... I'm getting pretty close to the overflow thing, curious to see how it works. To be honest the previous update was kind of bullshit, I thought it would overwrite common junk cards with rare cards as I earned them but that didn't happen. Before the original patch I made an effort to clear out some cards so I didn't accidentally overwrite all my spare titans. After that more often than not I didn't, but awesome cards just disappeared into the ether as I earned them. I'm thinking I missed out on a least a dozen spare titans and a dozen map hacks and the like.
What I'd really like, Respawn, is a system where I could just prioritize cards and have it run on autopilot. There are lots of ways to approach it. You could have an alphabetical list of all the cards. The use could scroll through and assign a class to each card... say Junk/Bronze/Silver/Gold/Diamond. Whenever a new card comes in, if it's say Silver, it will replace any card in Junk/Bronze if there's no room. Then within each tier the algorithm would just strive to keep things balanced, if it's a silver level card and you're already stacked at that card, it would discard it. If it's the other way around and you don't have many of those cards in that tier, it would discard one that you have more duplicates of. The longer you play while not using your burn cards, the better your deck would get. Eventually you'd only have Gold/Diamond, and finally just your preferred Diamond cards. I think that idea is pretty simple and immensely useful.
Otherwise, getting more complicated with it, I'd give the user a ranked list of all the card types to indicate priority, instead of tiers. And the new cards would simply obey the ranking system, i.e. are they high enough ranked to take one of the deck spaces from a lower ranked card? If so dump the lesser card and add the better one. Additionally you'd have another column, called "Protected Count" or something with a +/- button where it just changes a number next to the card. No matter where a card is ranked, if you give it a protected slot, however many you pick will be completely safe from culling. Your protection count can only add up to however many deck slots you have in total. So for us Gen 10 guys we'd have 100, and somewhere on the screen there'd be an indicator showing how many protected slots are still available. It would essentially define your ideal deck. But it doesn't even have to be that rigid, you could just use it to preserve some diversity. I could have my top tier not be protected at all, all the unprotected slots would prioritize those cards anyway. I could use just a few protected slots on things like Amped R101Cs and Smuggled Stimulants. Things that I don't think of as super high priority, yet I feel I always want a few in my deck.
That would also be a great mechanism for the 'collector' type to manage their deck. What I mean is that you'd set each card to a protected count of 1. That way you could earn a complete deck without having to micromanage everything. I think at gen 10 you'd probably still have some slots left over and that's where they'd get filled by your rankings.