It's just three years since former General Thein Sein emerged into international prominence as the first elected president of modern Burma/Myanmar in more than 20 years. At the time, not long after a fatally flawed election process, expectations that Myanmar had begun a genuine political transition were not high.

Yet Thein Sein's performance as president has probably exceeded most expectations.

Thein Sein's inaugural speech on 30 March 2011 was important in setting the aspirational direction for the country, which Myanmar's people and the international community both wanted. From economic policy to political reforms, it set a reformist tone and high goals, transcending short-term political objectives.

Subsequently, Thein Sein has shown firm leadership, and has generally proved a credible and popular leader. He has been decisive at times, and responded to domestic opinion in a manner not previously seen in Myanmar. And he has publicly advocated a strategic national agenda.

Thein Sein was in many respects working from a blank canvas, but has engaged constructively in a contest for authority with the new parliament, including in introducing mechanisms to improve checks and balances in Myanmar's fledgling democracy. He was able to set up effective working relationships with parliamentary members of the majority Union Solidarity and Development Party, which he previously headed, as well as with opposition leader Aung San Suu Kyi.

History should judge Thein Sein positively, although he is still criticised for not engaging in more thoroughgoing reforms. His most important achievement may have been his clear political commitment to a nationwide peace agreement, although completing this process has proven frustrating and complex. He is the first Burmese leader to attempt this on a national scale and with an open and systematic framework for negotiations, although some would argue that the process has been too bureaucratic, too cumbersome and too slow. Yet apart from the two obvious problems — the unpredictable issue of the Rohingya minority and the predictable resurgence of the Kachin insurgency — his government has made more progress towards consolidating peace than any predecessor.

Thein Sein's personal qualities have undoubtedly contributed to his success.

By reputation he is honest, not corrupt, and not personally ambitious. These traits have been important in generating badly needed legitimacy for his government. His readiness to take an inclusive approach to the transition, especially by reaching out to Aung San Suu Kyi, is also surprising and welcome. This was in striking contrast to the approach preferred by his predecessors and is proving extremely effective.

It took some months after Thein Sein's installation as president in 2011 before concrete reform measures began to emerge and gather momentum. This delay was perhaps because nobody knew how to translate long-term goals and reforms into concrete policy and action. There was no single transition 'model' and no international plan to help; indeed, the international financial institutions were missing and the UN was bogged down. Moreover, on most issues concerning the national development agenda, no clear national consensus or direction had been established and domestic opposition groups had not focused effectively on alternative long-term policies.

Thein Sein's most significant political decision was his suspension in September 2011 of the Chinese project to build the Myitsone Dam on the Upper Irrawaddy River. Not only did this powerfully demonstrate government concern for the ordinary people and play to popular opposition to the project, it also changed Myanmar's relations with China, placing them on a more equitable and sustainable basis, while ensuring China would comply with Myanmar law. This decision will probably prove to have been a major factor in Myanmar's future international standing.

The Myitsone decision was a turning point in terms of winning public approval, including among the younger generation, and provided Thein Sein's government some legitimacy in the eyes of the people. It was the first decision that inspired hope in younger generations and in ordinary people, and which showed that his government supported environmental protection and land-owner well-being rather than just crude economic interests.

Equally, Thein Sein's readiness to transform relations with the US set an important new direction for Myanmar foreign policy which is unlikely to change or erode in the foreseeable future. That international sanctions against Myanmar quickly ceased to be an issue, when they had dominated international discussions on Myanmar for more than twenty years, is also among Thein Sein's achievements. President Obama's visit to Myanmar in November 2012 consolidated a major shift in US relations with Myanmar which continues to gain momentum.

History may still question whether or not more concrete progress might have been possible in Myanmar's reform process, although observers underestimate the task of changing popular mindsets. Thein Sein faced major challenges in consolidating his position of president because he was not the most senior ranking general when he assumed the post. A major failure has been his inability to assert his authority over the Myanmar Army, which has essentially not complied with his directions to cease fighting the Kachin insurgents in the north.

The future of the army's role in nation-building remains an important piece of unfinished business. Indeed, whether or not the army will accept a background role rather than a dominant position managing national affairs remains the biggest question mark over Myanmar's political transition.

Thein Sein's failure to make more progress on reinstating the rule of law in Myanmar is a considerable disappointment. Serious human rights abuses continue, especially at the hands of the army; the judicial system is highly corrupt; the military still enjoys impunity; and land rights for ordinary people have not been assured. Some progress has been achieved in restoring freedom of speech, freedom of assembly, and the right to strike, but beyond these, wide grassroots reform has yet to occur.

Thein Sein's role as an 'agent of change' now seems about to end, but his successor as president is still not clear, nor is what happens next in Myanmar's transition.