but, i think the greek concept of multiple gods fighting for control is a much better reflection of reality than the hebrew concept of this omnipotent entity that is pure logic and wants to get in your head and own you. while both religions are obviously ridiculous, it is the greek religion that has a stronger empirical basis and that i'm far more likely to take seriously.
so, no, i don't think it's obvious that a god ought to be rational, and i don't think it's axiomatic that there ought to only be one of them, if there are to be any at all. and, when i break from these axioms, i really change the discourse.
but, i think you have the burden of proof to tell me why i should take monotheism more seriously than polytheism, or why your conception of god as rational is more believable than some other conception of god as irrational, or arbitrarily driven by emotion. we don't have a centralized theological bureaucracy that enforces this kind of bullshit at the end of a sword, anymore. you have to make your argument if you want to be taken seriously, as none of it is at all obvious.
and, i think this is healthy, because if we're to return to some form of religion, we should be questioning whether the jewish or greek systems are actually really preferable. the bottom line is that we may actually succeed in getting people to behave more ethically if we adopt greek religious ideas in place of jewish ones, as they conform more closely to empirical reality.
regardless, you have to make your case - i won't accept your axioms. they're just simply not obvious.