What is your opinion on Zulfikar Ali Bhutto?
I do not know if my opinion will be welcomed but as an Indian I want to answer this as this answer does not explicitly ask only pakistanis to answer.
So I will talk of his positives and negatives separately.
Founded OIC which greatly benefitted pakistan. Pakistan got better ties with many countries and many regions started looking up to pakistan. Pan-islamism was the reasons many kashmiris shifted their loyalties from India (they actually helped Indian forces to identify infiltrators in the 1965 war), baloch militancy was pacified after their revolt in 1972–73 and many added benefits.
Nuclear program was conceived under him. The only thing which saved pakistan from direct invasion by India or US in present times is nuclear weapons.
Alliance with China was forged when he was foreign minister under Ayub Khan government in 1963. China was also a strong ally for pakistan during his premiership. He even facilitated in US-China improved relations.
Abrogated State Subject Rule in PoK and made it de-facto pakistani. No more ‘bohot azaad kashmir’.
Introduced socialistic reforms for pakistan and stood up against crony capitalism, although he could not do much on that path as Zia stopped him with the backing of US as US conspired to kill every single socialist in muslim countries where they almost largely succeeded.
Tricked Indira Gandhi into releasing 93000 POWs and still not having to give up PoK, he pulled off a very profitable deal if we see it from a perspective of a leader of a nation humiliatingly defeated in war.