Question: I have heard that traditional dresses are better for so many people. But each culture has it's own version of traditional. I am a convert; I have been told that Pakistani garments are more modest, that Afghani garments are more modest, that Saudi garments are more modest etc etc. 

But they say it is inappropriate for women to wear things that are in their culture men would wear only, like pants from Pakistani culture (though it is traditional for them, women have only worn pants in the west for under a century). 

I can not wear thin silks and light cottons in northern Alberta; it seems very non-practical and false of me to wear the garments of other cultures, yet our imam seems to think that more traditional garments are better. 

I am thinking a petition in our local mosque encouraging Muslim women who are new to Canada to dress warmly instead of freezing in their cultural clothes with a used winter coat collection for those in need; this has nothing to do with showing skin or not wearing hijab. How would I go about convincing those in need to dress for the cold, so they don't get sick or have to suffer?

Answer: 
In Islam, both men and women are obligated to dress modestly and protect their chastity. There is no restrictions on what they wear as long as they dress according to the principles of Islam. You won't get any extra rewards for wearing a Pakistani dress or Saudi dress. There is no distinction between cultural dresses (Afghani dresses, Pakistani dresses, Saudi dresses) and simply modest dresses in Islam.
The Islamic injunction on dress is simply to drew modestly. There is no injunction on the exact form of dress. Thus, how you interpret this, is entirely upto you.

Most people I know who wear traditional Islamic clothes were born in the subcontinent and immigrated to Britain; and given the climate, they just wear sensible British coats when it's cold over their usual clothing.