Would like to focus on bolded sentences
Coincidentally my own grandparents had also migrated from Princely State of Hyderabad (Deccan). Plus all these provinces were made during dictatorship(s) of Ayub Khan and/or Yahya Khan. They say even Karachi was made a provincial capital of Sindh when there were options of declaring it a Federal/Union Territory or a separate province. But notable leadership among Muhajirs that time especially Nawab Muzaffar Khan (I guess that was his name) was not visionary or dedicated enough. There was a movement for Karachi province in 1970s and the man who led it was Mirza Jawad Baig...but our immortal "Democrat" Bhutto sahab crushed it through unethical means. After formation of APMSO , rest is history. Even Altaf Hussain is a Frankenstein's Monster of the same Neutrals.
Regarding Urdu language, what (other) language would be medium of communication if villagers from Central Punjab, Seraiki Belt, interior Sindh and KPK are put together? Is it Spanish, English, German or French? Punjab has also made valuable contributions in development of Urdu. Allama Mohammed Iqbal, Krishan Chander, Rajinder Singh Bedi, Bollywood lyricist Gulzar, Faiz Ahmed Faiz and Habib Jalib are/were all not just from Punjab but born before partition...So there was no imposition atleast when it comes to Punjab.
And as mentioned, there was a fishy business of bribery to divide/partition Punjab. In addition Muslim League had formed provincial governments in NWFP(now KPK) , Sindh and (United) Bengal....And as per certain Indian Liberal pages/sources, guess who were allies of League over there against Congress and Abdul Ghaffar Khan? Hindu extremist groups like RSS and Hindu Mahasabha......if these were foundations and materials from those days then what outcome can one expect? They say that even Quaid-e-Azam Mohammad Ali Jinnah was never liked by senior leaders of Muslim League.
Its not about having one national language.. it would have been better to declare multiple national languages... because having urdu as national language actually divided the nation rather uniting them. I would say all 5 regional language should be declared as nation languages along with urdu being official government language (which is english btw, even today)
i personnally support smaller administrative units but only if we have a simple governmental structure.. now having 40+ provinces, all having local bodies, then provencial governments and cabinets, and governors is too much burden on the economy... its good to have small units with presidential system and lesser ministries (why textile is a separate ministry, why not just trade etc)
The issue with partition was that the muslims demanded separate country and that was also in favour of west (less for UK, more for US - Atlantic Charter) because congress was little more inclined towards russia, and having one stable country here who can stand with russia was not in favour of west (specially having china and japan in east as well) so they wanted to destablize the region and thats why they divided india and created problems for them to keep them busy fighting each others. Now after partition, jinah was surrounded by british loyalists such as ch zafrulla khan qadiani who was the biggest supporter of west and went for USA despite having first invitation from russia.. you can read a lot about him how he was rewarded by west for his services.
most of the islamic religious parties including JI, JUI and many more were against Pakistan and only modoodi had a vision, he was of the point that it will divide muslim majority into minority and will be harmful for indian muslims and thats was very legit opinion.. other mention is wali khan. he was against pakistan because pashtuns were never a part of india... brits managed to occupy some land of NWFP and that divided the pashtun tribes... so Durand Line has no importance for pashtuns because for them its just a line and nothing else... and thats pretty much the same story in all british/western colonies (just look at straight lines as boders between african countries). so he can also be justified.
problem was with first army chief as we inharitied army from brits, we had first 2 commander in chiefs who were british and they damaged Pakistan to an extent it can never stand again... first pakistan did not send its troops to help kashmiries when they were about to takeover srinagar, second we did not claim indian states of deccan,junagarh etc (a trap from UN for ceasefire to stop kashmiri fighters and not claiming hindu states because it would have damaged our stance on kashmir.. and we ended up with nothing). and third we were made dependant on US/west for all army needs...