I was taught government in my secondary school days & when the parliamentary system of govt is compared to d Presidential system, one of d edges d former has on d latter is dat it is very cheap.
Note: In a parliamentary system, the hard of state is different from the head of govt(Nigeria practiced this between 1960 &1966 when the military stuck). while the presidential system is a form of govt where the executive power is vested in one person being the head of state & govt @d same time(as it is today)
what's ur take?

Nigeria is an heterogeneous country (where there are many tribe and languages) which make it to be a good reason to be a parliamentary country. Also parliamentary system is very cheap to run than presidential because in parliamentary system of government there will be no minister for state one or two as we have it now. I look forward to the day Nigeria will change her system. GOD BLESS NIGERIA