I'll start off with my opinions on the listed categories. As a long term collector and player of the game, I would be disappointed if old cards were not usable in some capacity. But having old cards makes a unnecessarily high cost of entry for new players. Magic solved this problem by having different formats. Additionally, many of the good cards in circulation have been snatched up by high profile collectors, leaving scraps for rest of us. This has driven up the price of the most playable cards because the supply has piled in certain persons' homes. Old Codes
While this would make players happy knowing that they can take their old collection online, this will also allow for a lot of abuse. Years of codes not mattering have let uncensored cards proliferate the internet. A person using image recognition and a web scraper will be able to make off with a huge bounty of codes they could sell in underground market. On the topic of codes, the way Chaotic synced cards was really cool and all, but its generally a pain to upload collections. Entering the digits was a tedious process.Banlist
This game needs a banlist. Especially if older cards are playable. As a community leader, we developed a list of cards that broke the game, or caused unfair advantage for their inclusion. These decisions were often hard to come to agreements but were done in the interest of the health of competitive gameplay. They allowed for many more decks to be playable which increased the satisfaction players had with games.Formats
If old cards are to be included, to aid with the cost of entry for players, I'd suggest having a legacy and standard format.
The game was designed for 6v6 with masters rules. Opening the game to 10v10 would be fun in a casual setting, if certain cards are banned. Based on card interactions, for each amount of cards, I'd suggest having a different list in each format. 1v1 was really a waste of an option, so if that doesn't come back I wouldn't mind it being replaced with 10v10. 3v3 can stay as a quicker game format, but the reduced with 5 locations and 10 attacks, really neutered gameplay. Attacks cycling so quickly meant seeing that 5 build point on hit wonder even more frequently. Same with oppressive locations.
Some of the existing cards are excessively strong with 2 copies. I think Chaotic could also benefit by limiting (turning unique) cards like Neekwin or Ursis. Though we were able to improve the metagame through a banlist exclusively, we did experiment with a limited list.Variable Stats/Energy
Variable stats was an innovative market gimmick. Lots of casual players love the idea because it means that duplicates can have varied uses in different decks with different discipline focus. It also means that in mirror matches its still possible to win a challenge against the same creature. But the offender is energy. Having variable energy, means that 2/3s of all cards were automatically bad. There was never a reason to pick a creature with lower energy in deck building. This makes players even more disgruntled when pulling cards. Especially on higher rarities. Just getting a Maxxor was supposed to be an amazing experience, but getting a minimum energy one would ruin the joy. At a competitive level, this means that decks that would already be expensive, require even more money to get max energy on every creature. This creates an even higher barrier of entry for players and is offputting.
I'd propose to completely get rid of variable energy and make it so that fully max or min disciplines won't exist. Like in a video game, if each card has a "pool of stat points" that would get randomly distributed for each discipline. In this way, you can have even a higher variance per discipline while preventing highly disparity between cards. If you have a "net of 0" and a variance of +/15 per stat. This will give many different combinations of cards but it means there won't be a absolutely terrible or strictly better version of a card. Cards can have different usage based on the stats. If I have a courage based deck, I'd use the card with higher courage. This decision making is killed when there is a card that is max or near max with all 4 disciplines. The richest "whales" would just hoard those and have significant advantage over others.Releasing Sets
Chaotic's sets were released at too rapid of a pace. While this is great for selling cards and collectors, casual players struggled to amass collections and keep up with the quickly changing game. The meta did not have time to stabilize, so problems with cards weren't noticed until many sets later. If there was more time in between the release of sets, this would have allowed the design team more time to respond to problems with appropriate solutions. An example I'll choose is the M'arrillians as a tribe, they were released and instantly had tools to counter them. The designers assumed their M'arrillians were going to be insanely powerful with their new mechanics, and provided answers that were overkill. The M'arrillians continued to be bad because they were released so quickly with more of the same: low power level and strong counters. Then they were defeated and gone. This all happened within a year. Its like the M'arrillian invasion didn't even happen, or was some side quest in a game.Card Accessibility
There needs to be reprints (not functional reprints) of core cards. Especially attacks. The game already reprinted lower rarity cards for the starter decks which was an excellent decision. But this needs to be done at a much broader range. A lot of the 1 bp attacks make up the majority of deck building decisions. Additionally, some attacks could be reprinted at lower rarity but keep the same name for rule of two purposes. https://docs.google.com/spreadsheets/d/1weORBAGY18F6-o2fRznxpMSK0DgR1ePCcODk2yBOmKQ
I was really happy when Chaotic went from a 5 card rarity system down to a 4 rarity. This put it in line with other games and helped pack balance within the last set. That being said, I believe that a 1/24 chance for ultras is anti-player especially with the variability of disciplines. A 1/9 would be in line with Pokemon's"ultra rare" pull rate. Additionally, when having promo cards, they shouldn't be cards that have outstanding gameplay value, specifically, Ikkatosh Aich King, Droskin, Carniwin. Having staple cards that are very limited in circulation put an even greater burden of entry for players. And if a limited card is sought out by players, it also makes it harder for collectors.
Other card games allowed for foil and non-foil variants of cards. I believe a good idea for Chaotic would be to have Commons and Rares not be foiled, but randomly would be foils of these in a pack. Supers, Ultras, and Promos can always be foil. Pokemon, Magic, Hearthstone, Yugioh, etc. all do this for their cards. Collectors would love to have full collections of foils, and flex with full foil decks.
I don't think that Unique should be on cards that are rare and lower. If an ability or card is so good that it needs to be limited, it shouldn't be that easy to get anyway. When opening a box of cards, and you end up with 2-3 unique rares in a box, that really feels bad (and no you can't just "trade them to a friend" because they also have 2-3 of it). On the topic of Unique, I think that every ultra rare card should have been unique. Hearthstone does this with its legendaries. Ultras are hard to come by (especially in Chaotic), and they are inherently power creeped over other rarities. This means that throwing more money at a deck can directly correlate to it being better. Having two Ursis, Tarterek Psi? Those cards are already ridiculous at 1, but with 2 they can sweep up decks.Card Balance
Recklessness is a mechanic that can automatically make a card bad. Combats last at least 3 turns typically, so a Creature with recklessness 5 needs to have 15 more energy than the typical fighter to make it worth it. Most of the time, the card itself was fine if it did not have recklessness.
Mugic Counters are an important part of the game, too often cards just can't find a place in a deck because of the inability to pay for all the mugic, so a fighter that could have otherwise been a good choice is completely glossed over because it has 0 mc. A card needs to be exceptionally good to make up for the lack of mugic ability.
Gain/Lose vs Heal/Deal
Because healing can only be applied to damage already taken, it makes dealing damage significantly better. I cannot respond to damage being dealt with a heal. Take for example: my creature starts with 60 health, if my opponent plays an attack that would deal 40 damage and chains a cannon of casualty to it, I cannot use song of resurgence to survive, I simply will die without an energy gain. Let's say I had priority and will "predict" damage being done and play the heal before hand on the burst. To which end the opponent will just not respond with a dealing ability and wait for the heal to resolve. Since no damage was done, no healing is done, then the attack goes through, I have wasted my heal, and my opponent can now play their cannon to finish me off.
It is my belief that when it comes to most Mugic and some activated abilities, those should be Gain while innate abilities, triggered abilities, and attack effects can remain as Heal. That way Mugic and abilities that would have healed nothing can be used as responses to other actions that would deal damage / remove energy.