The most relevant academic paper in the wake of SAFTA’s creation is “South Asia: Does Preferential Trade Liberalization Make Sense?” by Arvind Panagariya. In short:

The move towards preferential trading is a mistake, at least from the viewpoint of India. India continues to have very high trade barriers so that the scope for trade diversion and the losses accompanying it are likely to be considerable. Business lobbies being relatively powerful in most of the countries in the region, they are likely to exploit the rules of origin and sectoral exceptions in these arrangements in ways that will maximize trade diversion and minimize trade creation. In as much as the rules of origin give bureaucrats power, employment and opportunities to share in the rents created by tariff preferences, they too will become active parties to the diversionary tactics of business lobbies. Therefore, the member countries are better advised to proceed along nondiscriminatory lines in achieving further liberalization.

The PDF is here.