What you guys are saying is something that would help out your own decks, but what I'm thinking about is from a game balance perspective. I think that increasing the Extra Deck size would completely destroy the current balance of the game. The current number is good, because it allows players to have a bit of leeway with their picks for their extra deck, getting the cards they need for their deck, as well as some extra cards for support. If they reduced it to 10, I think that it would force players to consider their choices of monsters for their extra deck more carefully, making it more important to use unique cards that fit their deck better, as opposed to filling their Extra Deck with staples (e.g. Stardust, Blackrose, Utopia, Maestroke, etc.). I think that it would just create more of a tactical game.
To elaborate more, I think that if they increase the number of extra deck cards, every deck will be focusing on spamming everything they can in the Extra Deck. More Chaos variants of decks such as Shaddolls, Zexal Weapons, or even the ressurection of the Elemental Heroes and Gem-Knights. The entire meta of the game will become "Who has the better Extra Spam Deck?" Everything will either be focused on spamming the field with Extra Monsters, or keeping people from spamming the field with them.
Last edited by Shadow Direwolf on Sat Sep 12, 2015 6:19 pm; edited 1 time in total (Reason for editing : Another thought popped into my head after originally writing this.)