Polytheism is more rational than Monotheism, Monism or Pantheism
My thesis is that Polytheism is the most rational form of belief in gods/goddesses, because of the following points:
1. Polytheism has no moral and ethical contradiction
Because there are different gods, there is no unified moral, ethics or punishment. The world is good and pleasant, but also to the most part bad and cruel, because different forces are fighting for their existence and the favor of the people. The suffering on earth is grounded in the lack of an almighty creator, that would have the compassion and might to stop violence and suffering. If Pantheism would be real, the Pantheist god would have to be not better than the average human in a moral sense, because he/she would be to the most part ruthless and cruel. There would be no reason to worship him/her, because worshiping a compassionate human being, would make more sense. The different deities of different religions have different characters and stages of compassion, so therefor humans can choose the most lovingly deities, who have good intentions towards people. This is more rational, than worshiping an mostly evil pantheist, monist or monotheist god.
2. Polytheism explains why there are different religions and different gods
While monotheism has to negate that other gods exists, polytheism doesn't have to negate their existence. The actual reality shows, that there are different kinds of gods, religions and revelations, which can by monotheism only explained with lies and evil(Satan, Demons), while polytheism can accept all forms of belief as an expression of divine diversity.
3. Polytheism is more in line with evolution
Polytheist creation stories explain evolutionary processes as ancestor lineages and the becoming of the conscious, out of the unconscious. This is reflected in for example the Norse or Greek creation myths.
Polytheism knows deity families and lineages, also ancient ancestors like the Titans, while Monotheism negates evolution and claims there always had been a god that created the unconscious and conscious. But consciousness requires unconscious matter as a reason to rise up, so polytheist, non-creationist deities out of matter, are more realistic.
History and archaeology today makes it possible to trace back the evolution of gods and religious concepts, there is no doubt, that all that is based on the principles of evolution and not on a single revelation by one or few persons.
4. Polytheism requires no almightyness
While Monotheism, Monism and Pantheism leads to acceptance of an almighty god, Polytheism does not require it. If a single god is almighty, he is not able to make mistakes. He would be a perfect programmer and everything he/she does, would be perfect. But we know from the Christian scriptures, that Yehova is angry, jealous and in bad mood. But an almighty being could not create something, that would make him angry, because anger is a product of evolution and a mechanism to cope with challenges and find a way of resolution. An almighty being, cannot be challenged, because it does not require evolution. Evolution is a sign of imperfection.
If a Pantheist god/goddess would be almighty, he/she would have the qualities of the actual world, which would make him/her not better than the average human, so therefor not worth to worship or listen to, because of his/her cruelty and ignorance which exceeds the good things.
If an almighty Monistic god would have created the actual situation (Over-presence of suffering in the world) to have a divine play with the living beings, he/she would need a lesson in compassion, not his/her victims. It would also not be a good idea to worship him/her, because this would lead this deity to believe, he/she is doing the right thing.
If a single god is not almighty, there must be more than one god, or this god must have weaknesses and imperfection, which would mean, that his creations, could once become a better being than him/herself. So Apotheosis would be a spiritual goal, which would ultimately lead to polytheism.
So therefore, imperfect, multiple gods are more realistic, than a single, almighty one.
5. Polytheism is the most ethical choice
Taking into account the previous points I made, polytheism is the most ethical choice, because one can choose which deity has qualities, that are good for humanity, animals and the whole planet. This would people force to choose a compassionate, friendly and parenting deity, instead of choosing an angry punisher, or sadistic divine player. Pantheism, Monotheism and Monism on the other side, don’t have a choice, because there is only one deity, who as to be accepted and worshipped with all his/her failures, ruthlessness and evil.