In my efforts to create a perfectly balanced set of Yugioh cards for the purpose of establishing a benchmark for custom card creation, I realized that there are two fundamental balancing flaws in the design of Yugioh cards that outweigh pretty much everything else
1.) Abilities are worth more than it costs to play them.
Now you may think: "Doesn't it make sense for cards to be worth whatever it costs to draw them?" Thinking that way assumes that it's fair to have a spell card that simply says 'Draw 1 card.' You are using the full value of a card to draw another card. After you're done, it seems to be an even exchange and nothing has happened. However, I believe that not just for card draw, but for anything worth anything in a game, having unconditional even worth is bad because then it's too easy to gain conditional infinite advantage. For example: Cards of Consonance into White Stone of Legend. This converts 2 cards into 3 cards. It's generally expected in this game that a good card has some way to gain card advantage like that. If you have a bunch of scenarios in your deck which allow you to generate more cards from less, you basically end up with the 1 card combo nonsense that we deal with today.
2.) Extra Deck slots are treated like cards you had to draw. If you've played hearthstone, Extra Deck slots are basically like Hero Powers. You always have access to them. It would be expected that as an ability that you don't have to draw, and you simply always have access to, it would be weaker than a card you would actually have to play from your hand, because when you play a card from your hand, you lose card advantage, by consuming that resource. In hearthstone, the hero Powers are clearly an inefficient use of Mana, which is good design, however, in Yu-gi-oh this is not the case! Extra deck cards are very strong, and are often the most powerful cards in a deck. The game has basically become all about these extra monsters, even though from a design standpoint, all these cards should be weak because of their accessibility.
The question is: knowing that these are the issues, what is there to do? I think that ideally we create a world where the custom cards don't have these issues, however, that seems unreasonable given the generalized acceptance of these concepts by the playerbase. What seems more reasonable is to simply keep these rules in mind when designing cards, and consider the power potential of a deck as a whole when considering design. I feel like custom card design should go more towards custom deck design when considering these facets.
Idk. These are my thoughts. What do you think? Are my feelings reasonable?