Muslims shouldn't reject the shariah law just because you think it's archaic or unsuitable for our "time". If you believe in the religion, the scriptures are timeless and applicable throughout time.

Don't play God by trying to shift and disprove what's written. But here's what you can do, educate yourself to understand and differentiate what is written, and what was derived and interpreted. The shariah law is absolute, to those who claim to be believers of the faith. But interpretation are done by man, and man is flawed.