I dont think anything is wrong with Mormonism. ~shrug~ right and wrong have to do with moral issues, and spiritual develipment/enlightenment intended for a benevolent purpose cannot be 'wrong'.
I do not believe it is unethical to be mormon either. Christianity has a VERY LARGE SPECTRUM of denominations, and they all have their own unique quirks, beliefs and systems. I don't think one can say any single one of them is wrong, or misguided.
For aren't we all guided by one God?
yes Ive heard that mormonism believes in reincarnation in a sense where, the better you are on earth, and the more wives you have, the more godchildren you will be given on your own planet somewhere else in the universe. I don't know if thats necessarily what they believe(Ive spoken to many mormons, and all of them were not aware of this idea), but all religion is skewed, clouded, veiled under mysterious riddles, puzzles and rubixcubes, and I believe that mystery is one of God's greatest assets, for God works in mysterious ways, and if all truth was exposed in the Bible, then there would be no mystery to God's majesty, would there?