I know a lot of folks here hate it when other players try to defend FFG. Nevertheless I thought it might be fruitful to note that even with playtesting it's quite natural for errata to show up. While I'm sure that FFG has a group of playtesters that aren't involved in game design, etc., I also imagine that a good deal of the playtesting is done by Caleb, et al.
When a person works intimately (yeah I used that word, get over it) with any particular work (book, article, etc.) or project (game design, etc.), tunnel vision can occur, by which I mean that sometimes one couldn't even imagine a card, after the hours of design that go into each, would interact with this card, or combo with that card, or create an infinite loop here, or break this enemy, etc. Things get overlooked, it happens, are you over it? Furthermore it's simply not possible to look down the road at EVERY SINGLE FUTURE CARD to predict interactions there. I presume there's a plan, but I don't think the entire lifespan of the game is mapped out and hanging on Christian Peterson's office wall.
Yes, errata correct mistakes, but they also keep the game functioning at a reasonable level without letting unintended consequences slip through.
In any case, I know some folks just like to complain about this, that, or whatever (all three of which are sometimes cards erraverunt (that's the real word, for more than one card, that should be used in place of "errata'd")), and this post won't change that, I just wanted to put my feelings about all of the negative commentary.