Islam owns atheism with a single verse

[Loaded dice]

God as traditionally defined ™ is a necessary being, a being that cannot fail to exist.  

God as traditionally defined may or may not be a necessary being. The concepts of necessity and contingency are completely absent in all the major scriptures of the world religions. For all we know, the account of God in Islam may actually be that of a maximally great being, but not a necessary one, just enough power and "greatness" to make creating the world possible.

And it's worth noting that the only theistic arguments where necessity matters are ontological arguments, which are of dubious validity.

So it seems scope of conceivability is inversely proportional to the scope of knowledgeability, no?

I don't think it's bad or subpar if we try to conceive of things that aren't real. We have a vivid imagination, well, let's use it.