I admit that it can be hard to tell how strong a certain decktype will be. Not because its difficult to build a deck like affinity (this is not a creative deck, its easy), but because it can be hard to tell how good the players will be to create decks that can beat it.
But I still think the broken cards might "slip through" intentionally. I dont know, but I think its very probable. They are only a few people, but someone actually created every specific card. I believe this guy works fulltime at Wizards. How can he miss it? I dont believe a card is made in 30 seconds. This is a major bussiness. Every single card needs lots of work. At some point his workgroup will evaluate this card. Is it worth printing? Is it interresting? Are there ethical problems? Problems with law? Is this card broken? Wil it be a rare, an uncommon or a common? Its a long process. I cant believe that noone asked "What if I have 2 of these and sacs one?". This card has "COMBO" written with big letters on it.
I know that I´m a little harsh, but generally I dont believe a word of what what they say. They have always some kind of logical explanation, but their logic changes now and then, and is rarely consistent.
A while ago they decided to change the way time vault works. NOT because of the newly flamevault combo, this was just a coincident. The problem had been there for years, and they wanted to fix it. Right...coincident...if the problem had been there for years, why fix it right now?
And then theres the usual stuf, basically "We are just some cool players like you, who wants to have some fun". No your´e not. You are part of a multimillion dollar bussiness, and youre are doing your work, which is making magic sell as good as possible. And they are actually so good at it that I dont believe in random "slip throughs".
But they have earned my respect in the overall way that they have handled the game. When I started back in 94, I didnt believe that the game would still be interresting 12 years after. They would probably be tempted at inflating the cards, sellng lots of cards for some time, but soon killing the game. But they didnt. Not much. They choose a long-term strategy. Good for players, good for bussiness. Someone at Wizards has proven to be very competent