Argentina, like most Latin American countries, would do well to toss the Presidential system. The US, by and large, has lucked out, in no small part to what Bagehot referred to as Americans' "genius for politics". But in other societies, where the legislative and judicial branches have remained stunted as compared to the US Congress, SCOTUS and the Federal Courts, all the Presidential system does is deliver near-dictatorial powers into the hands of the President. The checks and balances may exist on paper in countries like Argentina, but the reality is that legislative assemblies and courts become little more than rubber stamps.
A parliamentary system like the Westminster system would, I think, work far better. The titular head of state of a parliamentary state does hold some potent reserve powers, but is restricted from using them in all but the most extreme circumstances. The "effective" government, that is the governing Executive, only survives so long as the legislative assembly retains confidence in it, and ministers are normally chosen from among members of the legislature, and thus, at least in a nominal way, remain equals to every other person sitting in the legislature. In a parliamentary system, the titular head of state represents a sort of negative power; in that he or she deprives the effective executive of absolute control of reserve powers and prerogatives.