Pak-One, of course, no one can gaurantee (or ever has guaranteed) smooth parting of ways between ethnic groups in a distintegrating state. Neither, the spectre of bloodshed and forced migration have stopped ethnic groups from seeking autonomy and self-rule or outright sessation. If that were the case, bloodshed would never have occurred in East Pakistan and Bangla Desh and Pakistan would never have come into being (for fear of bloodshed, massacre).
Yet partition took place both in 1971 and 1947 (despite the scale of bloodshed). Were Qaued-i-Azam and Shiekh Mujib not cognizant of this? Were Yahya Khan and other generals not aware of the consequences of the extreme step they took in 1971? Of course they were but the dynamics of a failing/dyfunctional state and political system and resurgent political aspirations don't take stock of such issues.
And that is precisely the point I want to bring home.
Rest the conversion of Pakistan into a federal state, it would be better if that happens (there seem unfortunately little chances of that). And that is what would be a step towards an eventual soft collapse.
It's pretty interesting that you reference Quaid E Azam because according to the sources (both written and oral) he did not expect that grand level of violence and migration. In fact he fully expected the minorities in Pakistan to stay.
As for Mujib, he was the democratically elected leader of Pakistan and his devolution of power and the vision of federalism was much more in line with what the West Pakistanis were willing to accept. Also, you can not underestimate the fact that the violent Pak. Army crackdown furthered the spiral of violence. Many people argue that Mujib was secessionist from the start, but we will never know what the implementation of the 5 points would have entailed.
I do agree with you on the failure of the Centre. We are approaching a defining moment where many things can be possible. A united Pakistan that devolves power and grants sufficent provincial autonomy is in the best interest of everyone (excepting the entrenched elite).