Many people do not realize that the USA system developed over the 200 years post-Constitutional adoption in 1789. In the beginning the Senate was appointed by the legislatures of each state rather than being elected by the people. People without property could not vote for state legislators in many states. Slaves certainly couldn't vote. The appointed Senate "elite" moderated the laws that were passed by the directly elected House members for many years, until 1913 and the passage of the 17th Amendment. It required the growth of the American middle class over about 120 years for this change to occur.
Also, women did not receive the right to vote until around 1920, when the 19th amendment to the US Constitution was ratified by 3/4 of the states. This was 130 years after the US Constitution was first adopted.
So, it might be that Pakistan would benefit by progressing through a similar experience wherein, at first, there is a directly elected legislature and one that is appointed by the provincial legislatures. The appointed body would need to have some powers that "balance" the elected body until such time as there is the political desire to replace the appointment process with direct elections; i.e., until the Pakistani middle class has developed enough political power to get such a change in the Pakistani constitution ratified.
Of course, the election of the US President also changed over the 200 years from election by "electors" appointed by state legislatures to election by electors that are voted for by all citizens. Again this was a change process that tracked the development of the American middle class into dominance but required amendments to the Constitution, a difficult process requiring a 3/4 vote by the states, to accomplish the changes.
As for women voting, I leave that to you guys. It may be the reverse would be best for Pakistan. That is, at first let only women vote. In time, if the men can convince the women to share the vote, the women can change the constitution to let the men vote .....
The US Constitution, as amended over the past 220 years, is a style of governance with many checks and balances. Its provisions are intended to keep the Federal government from becoming a dictatorship. The amendment process allows changes to be made as societal values change, but the amendment must pass both the House and Senate, be signed by the President and approved (ratified) by 3/4 of the 50 states within a 10 year period. The US Constitution was amended with 10 amendments (the "Bill of Rights") before enough states would vote to approve it at all (in 1789). Since then it has been amended 17 additional times to do things like: elect the president by citizen vote, free the slaves, give everyone in every state equal protection by the Federal Government, levy income taxes, elect Senators by citizen vote in each state, let women vote, prohibit the sale of alcohol, rescind the prohibition on alcohol sales, limit the President to being elected for only two 4-year terms and change the way a new President is chosen if one dies while in office. My point in raising this is that no perfect governance system can be designed that will be good for all times into the future. So the best way is to get one started well but be able to "amend" it, not easily, but when the society feels the overwhelming need to do so.