iranians are highly pro-indian as niaz said.
they support indian presence in afghanistan which is a clear threat to pakistan, if a country cannot respect our national security, and works to undermine it then the conditions are not right for any union.
they also have their own ports in competition with gwadar.
i dont trust the iranians, i understand their mistrust of pakistan because we are seen as a US puppet but why are they working against our vital national interests?
why do they not have a firm persistent stance on kashmir?
you cant fully trust people like this, and certainly people should not dive head first into romantic gestures of islamic brotherhood, iranians are selective muslims, lets see if they behave like good neighbors before we call them our brothers?
the turks are by large secular, you know where you stand with them, the iranians - who knows?
also as soon as we start talking about islamic unity this is going to get the whole western non-islamic world on our back - neither russia, the US, india and maybe china want a block of unified, well armed, nuclear armed islamic nations in eurasia, please talk sensibly, lets talk about building good relations to start with.......