Critiquing The Problem of Non-God Objects

Justin Schieber formulated an argument against the existence of God using non-God objects. Non-God objects are anything, such as a piece a paper, a planet, or plants. The argument is interesting and is valid; meaning that if all the premises are true then conclusion is correct.  Here is a video link of Schieber presenting his argument: http://www.youtube.com/watch?v=QuHyxZ_cylE

Here is the formal shorter version:
P1: If the Christian God exists, then GodWorld is the unique best possible world
P2: If GodWorld is the unique best possible world, then the Christian God would maintain GodWorld.
P3: There are non-God objects, this God didn't maintain GodWorld.
Therefore, the Christian God, as so defined, does not exist.

By P1 Schieber means that GodWorld is the unique best possible world because all goods maximized. All goods are maximized because  GodWorld is identical to God and God traditionally defined is a maximally great being therefore, GodWorld must also be maximally great. P2 and P3 do not need much explanation but just to be clear God would maintain GodWorld because God is benevolent or perfectly good which means He would, if there is a unique best possible world, choose to maintain it. 
 
   Now, it is unclear that there is an actually thing as a unique best possible world because there seem to be an infinite amount of possible worlds that are equally good. Take for instance GodWorld and compare it to a world where only some amoral planets exist. GodWorld and PlanetWorld should be both taken as equally maximized in goodness because there is no good reason to think the addition of amoral planets to GodWorld should degraded GodWorld. Schrieber is familiar with this response and he thinks  that even a single molecule added to GodWorld would degrade GodWorld. He uses this analogy: Take a pure cup of water and add anything that is not water to the cup, the cup of water would no longer be pure and this he thinks applies directly to GodWorld (1.). I found this comparison surprising because GodWorld and the cup of water are hardly comparable at least in the way Schrieber would like. At best this shows that once God creates from the state of GodWorld then God is no longer identical to the world He is in. This does not mean that the maximal greatness of the world is degraded which I think can be shown more clearly through a different analogy. Maximal greatness if comparable to anything would be possibly comparable to infinity. Now, take an infinite set of even numbers. It should be noted that the infinite number of even numbers still has as many numbers that any set can have. Let us add to the even infinite set; (5,7,9), then the infinite set is no longer a completely even one but is still an infinite set. In the same way if there is a maximally great world and non-maximally great objects are added to the world that does not mean the world as a whole is no longer maximally great. It should be noted that I am not wholly convinced this analogy works but if an analogy would work with maximal greatness it is infinity. Even if the infinite analogy does not work Schrieber still must show maximally greatness would be degraded if an any amoral object was added to it since his water analogy does not work and it is not intuitively obvious that GodWorld would would be degraded. 

 I think premise two is problematic as well but that is for a different time. As long as one of the premises is shown to be false then the entire argument falls. At this point there is reason for significant doubt regarding P1. 

 (1.) http://freethoughtblogs.com/reasonabledoubts/2013/08/03/debate-does-the-god-of-christianity-exist-max-andrews-vs-justin-schieber/