The pro of such a measure would be that it would increase the amount of democracy that we have in our country. It would allow the voice of the people to be heard on specific issues. This might reduce the power of interest groups and politicians.
The major con is that the people are susceptible to passing initiatives that sound good but which have far reaching consequences. When they vote for an initiative, the people do not have to do things like figuring out where the money for the program that they are approving will come from. This has often ended up handcuffing state governments in states where initiatives are allowed.