Well, see, from my perspective there really isn't any designer ever in the history of the world who has gotten things perfect off the bat. For the most part it takes a lot of learning, trial and error, and a little luck for things to come out perfect...and even then.
Indulge me for a second if you will.
Lets say God had his plan...the bible. In this bible there are certain things that come directly from God himself. One of these things is Genesis. The other is the end of the world and all that goes with it. Everything in between involves humans, and these humans seem to have influenced in one way or another the outcome in the middle.
So lets take out the middle part (the humans). What we're left with is a set of instructions/plans for creating a universe and everything in it. So lets say God started out with the big bang to get everything going, and then started trying to make earth the way he saw in his plans.
Earth 1.0 in a galaxy far, far away started the same as ours, they were given Gods word exactly how we were, but due to something not being tweaked just right (say the gravity) the humans in that version all became big blobs of flesh and didn't work out. So, then God chucks out that galaxy and starts again. This time, for whatever reason a water bearing planet doesn't work...just like how sometimes a cake won't rise, so...God starts again.
This might happen thousands, or millions of times until finally he comes to our Earth. Everything works out pretty good, except....crap, the humans start rebelling. God looks at it and says, "Hmm, this one is pretty good, maybe I just need to tweak things a bit!" So, with much regret he tells Noah, "Dude, build a giant boat...do it right the first time too cause I didn't make a whole lot of wood!" So he floods the Earth.
The point is that because we only have the word of God to go on (and the bible) we really have to believe whatever is told to us. If God says he's perfect, despite all the imperfect things we see around us we must still take that as truth because that is what is told. The thing is, God is kinda like his own TV station running his own commercials...he's not really going to admit his product isn't the best. Not only that, but things aren't going to work really well if the first page of the Bible said, "Earth, version 110.6, You all didn't work out exactly how I intended...close, but no cigar....but you're still special!"
The bible has to tell us we're the center of the universe, but taking all we know of design, the size of the universe, the unpredictability of things, and how poorly designed things are on our little planet it would seem to me that we could very well just be one in the long line of attempts God did. We would of course never know this because we have the bible telling us exactly what we need to hear.
To put it simply.
Earth #200345 - "I am God, I made you in my image, I am perfect, listen to me, here is how I did it....awww crap...blobs again!"
Earth #559335 - "I am God, I made you in my image....ooops!"
Earth #399827 - "I am God, I made you in my image, I am perfect, listen to me, here is how I did it......hey...awww man....Noah!!"
How would we know any different?