My opinion:
If enough Iranian oil is put on the market, it will help depress the value of oil and hasten the coming global financial crash (which would happen anyway, just some months later).
The financial crash will be initially deflationary at least for stocks, bonds, and real estate (as giant debts are defaulted on) then inflationary (for everyone, as world governments go full Keynesian and finally succeed in enormously devaluing their currencies). In the process, many people will lose jobs, and there will be increased political turmoil. Only once the gargantuan malinvestment has been liquidated and governments stop sabotaging free markets will things can get back to a growth path.