When it comes to ultra conservative dress code for women, it's adopted most by south Asians (most notably by Pakistan & Afganstan). Saudi & Qatar are the only countries in the Arab peninsula that follows the wahabi sect of Sunna .Many women in both Bahrain & Kuwait have abandoned the abbaya since the early 1960'.
The whole gender segregation issue have been causing controversy only in recent years. I think this is due to the wide spread of salafi cleric's fatwa through Internet and satellite channels