We believe in Allah's absolute Wisdom and Knowledge and Mercy,b that is why we never argue with any rule from Allah. We know that He Knows all the reasons even if we don't know. Real believers submit to all the rules which came from Allah (SWT) through His Messenger (SAWA).

We might know part if the reason but can never expect knowing full reason because of our limitations as human beings.

Woman covering her body might be related to the fact that woman in her nature is more attractive to men, that is why she needs to cover herself.

Woman is allowed one husband only at the time, because of her dignity and respect which part of her creation as a human female. Usually, noble females from any faith or religious or cultural background, don't accept nor digest having more than one husband at the time. That is part of her nature.

Wassalam.