As far as I know Zia-ul-Haq never enforced any dress code on the females.
yes he did. female newscasters were asked to cover up as someone has already said. also his islamization and encouragement to mullahism paved way for moral policing of women.
Burqa is not a result of Zia-ul-Haq Islamization or Arabization. It's the result of education.
Before many people were illiterate.They did not had any religious or non-religious education.
So they did not what Islam permitted or not permitted.They just followed the customs of the area.With time people got more educated and they started trying to follow Islam in everyday life.
My Grand Mother's generation had almost no formal schooling.They don't know anything about Islam.Most of them don't know how to pray Namaz or read Quran. They can't even read a single verse of Quran. Some even don't know the proper way to say the Kalimah!
The Kalimah that make us muslims.
My grand mother's generation is more concerned about local tradition,then about Islam.They never wore a burka,but they did wear a chador for purdah because of local custom.Their purdah was lax,not up to Islamic standards.
My mother's generations got formal schooling up to primary level and some Islamic Dars also.So they follow more Islamic principles in their lives then the previous generation.The do proper purdah,but they prefer the chador for it.
Now comes my generation.The females are more educated then the previous generations.Both religious and non-religious education.And almost all of them wear burqa and do Nikab. And my generation's female are more disciplined in following Islamic principles.
The reason of wearing burqa instead of chador is pragmatism, not arabization. Most of women cloths available in markets don't meet the Islamic standard for a femaledress.So,the women of this generation are forced to wear another piece of outer garment that covers them properly.And their choice of this garment is burqa.
Why burqa? Why not chador? Because chador is considered a garment for old and unfashionable people.Not for the young and fashionable people.And they find burqa more easy to handle then chador.
And you are making blanket assumptions against the whole nation.
Again you are making general assumptions, that those marriages that fail are result of being arranged.Don't love marriages also fail?In fact arranged marriages have much higher rate of success then love marriages.