Yeah it was a joke, I should stop trolling...
Ok, so I also have a serious comment on the topic. I think that the developer of a CCG should make an effort to make the game as fun as possible for everyone. This means that cards and mechanics that aren't fun to play with should be not as competitive as fun mechanics.
To give you an example of a mechanic that is rather unfun to play with: Quanta Denial. I didn't find it surprising that the two most frequent answers in this poll (
http://elementscommunity.org/forum/index.php/topic,4031.0.html) were Earthquake and Black Hole, even though none of those cards are particularly strong. Yes, Black Hole is part of a rather annoying FG-Deck, but Seism is pretty beatable for lots of decks nowadays. The reason for this that this phenomenon has been observed extensively in MtG with comparable mechanics. Players dislike it when they cannot even execute their game plan and lose because of it. They want to play their cards and interact with the opponents deck, and if they can't even do that, they get upset.
Another unfun mechanic is randomness. If players lose because of a random effect that they couldn't influence in any way, they get upset. You have to be careful here though, because randomness does not necessarily mean randomness. An example for a good randomness card would be Fallen Druid, because at the end of the day, he's not random at all. He basically just says: Handle me in now or in a few turns I've made an invincible army of mutants. An example of bad design would be cards like Mutation (the card), Chaos Seed or Dusk Shield. All these cards have a very high variance when you play them. Chaos Seed and Mutation are just one-shot hit or miss cards. Dusk Shield is okay when the opponent has lots of small creatures, but extremely swingy when he has only a few big ones. Even if those cards were buffed so that they were very good, I'still be reluctant to play them.
As for mechanics that are good, I like having lots of options and longer games. Examples for those cards would be Electrum Hourglass, Lobotomizer, Eternity or Shard of Gratitude.
Oh, and while I don't claim to be a YGO expert, I'm pretty sure that the 'god cards' aren't even good. The most overpowered card in YGO is called "Pot of Greed".