AS speeches go is was by any standards a searing indictment. United Nations Secretary General Ban Ki-moon, had chosen this moment, his final address to the General Assembly, to say what he really felt about those he believed were responsible for perpetuating the war in Syria.

“Powerful patrons that keep feeding the war machine also have blood on their hands”, Ban told delegates last week unleashing his outrage.

“Present in this hall today are representatives of governments that have ignored, facilitated, funded, participated in or even planned and carried out atrocities inflicted by all sides,” insisted Ban.

It couldn’t have been a darker address from the 72-year-old South Korean Secretary General, who is stepping down when his second term expires at the end of this year.

As Ban spoke, some 5,500 miles away outside the Syrian city of Aleppo, the charred carapaces of UN trucks that had been carrying humanitarian aid lay where they had been bombed.

The wrangling over just who was responsible for the attack on the convoy rumbles on, and gave US Secretary of State John Kerry his own opportunity last week to launch a blistering attack on Russia.

“I listened to my colleague from Russia and I sort of felt like we're in a parallel universe here,” Kerry said of their differing accounts of the attack on the convoy and the wider Syrian conflict

“The trucks and the food and the medicine just spontaneously combusted,” Kerry said. “Anybody here believe that?” he asked in response to one of numerous explanations offered by Russia at the general assembly as to what had happened to the convoy.

In all it was an exceptionally turbulent time at the UN last week. The anger, outrage, claim and counter-claim over the latest events in Syria has been one of the most testing periods for the international body in many years and once again thrown up crucial questions as to the validity and effectiveness of the UN.

As the organisation approaches the 70th anniversary of its foundation on UN Day on October 24, it is facing criticism and scrutiny perhaps like never before in its history.

Many point to its governing body, the security council, and how it still reflects that postwar world with the conflict’s victors – China, France Russia, the UK and the US – still the only permanent members, all with veto powers. They point also to a world that has changed enormously in that time, with new challenges posed by conflict, migration and climate change.

Given all this, is the UN still fit for purpose many now ask?

It is of course not the first time the UN has faced such pressing questions. Many of those who defend and support it say it’s all too easy to criticise but difficult to come up with a solid workable alternative.

When it comes to making the case for reform and restructuring however even the UN’s staunchest supporters now accept this is long overdue. Many of the UN’s systemic problems and the challenges it faces have been addressed in the findings of a recently published report entitled: UN 2030 – Rebuilding Order in a Fragmenting World.

Former Australian Prime Minister, Kevin Rudd, whose name was once mentioned among the potential contenders to replace Ban Ki-moon, insists the UN still matters, and “in many ways matters more than ever”.

“We are facing the biggest set of external changes and challenges to the global order since 1991, following the fall of the Soviet Union,” Rudd was quoted as saying recently. “Over the last 25 years, we haven’t seen anything comparable to the current state of great-power relations. We haven’t seen anything comparable to the current intensity of the globalisation process. We haven’t seen anything comparable to the emergence, for example, of terrorism as a mainstream threat to many societies across the world”.

These, insist Rudd, are new phenomena, which leaves the UN with no choice but to act. By way of example as to how these challenges have formed, UN watchers point to conflicts in places like Somalia, Nigeria, Syria and Iraq involving Islamist inspired terror groups like al-Shabaab, Boko Haram and Islamic State (IS) group.

All of these they say have evolved from particular local circumstances but often have a reach and consequence way beyond this, both regional and global.

In contrast the UN security council was originally established to help prevent and arbitrate state-to-state conflict, a mechanism that is now simply out of step with an entirely different world and the threats such as this it throws up. Everywhere new global fault lines threaten traditional patterns of stability and involve a new generation of lethal non-state players, principally in the form of violent jihadism.

These are just some of the factors that have changed the ground rules and subsequently the UN’s ability to respond. For these new players state-based systems mean little or nothing, as does international law.

So where does this leave the UN, and how does it go about addressing these and the other pressing issues it now faces? This too not least given also that many of the UN’s own most powerful members are as much part of the problem as they are the solution.

The recent bombing of the UN humanitarian convoy trying to deliver aid to desperate Syrian civilians in Aleppo is a case in point. Should it prove that the attack was carried out by warplanes from Russia, one of the UN’s own permanent members of the security council, then, understandably, serious questions arise over how its possible for the UN to change for the good.

Those problems of course stem not only from its most powerful members. That much was evident in Ban Ki-moon’ parting tirade last week in which he effectively called out half the leaders around him at the General Assembly. Referring to one after another nation among them, Yemen, Libya, Iraq, Afghanistan, South Sudan and Ukraine, Ban made his message clear.

“Serve your people. Do not subvert democracy; do not pilfer your country’s resources; do not imprison and torture your critics,” Ban chastised them.

Chastisement is one thing; ensuring good practice however is an altogether more difficult thing to pull off. A starting point many say would be for the UN to reaffirm its legitimacy and universality by having member states themselves formally reaffirm their own political commitment to the fundamental principles of multilateralism.

In a sense the world at large is in need of reassurance that the UN is not only capable but also genuinely willing to take on the global challenges that now exist.

“When the peoples of the world see growing disagreement among the great powers, the re-emergence of old interstate tensions and conflicts, terrorists on their streets, chaos in their markets, and jobs disappearing with nothing to replace them, they are increasingly asking: 'Is anybody in control anymore?' This is not an unreasonable question,” says Rudd, summing up this need for reassurance and reaffirmation of the UN’s role.

In tandem with this, others share Rudd’s view of a real need for structural change to take place and the UN to reinvent itself. This ranges from looking to build new bridges between great powers to developing a stronger policy planning capability that anticipates future problems rather that simply reacting to the crises of the day.

In other words, an emphasis on prevention helping to stop the slide towards cataclysmic conflicts like that currently under way in Syria.

For too long now the UN has been better at reacting to crises than anticipating them. Critics say there is a greater need for what they describe as “preventative diplomacy.”

Examples of this they say could for instance be the prepositioning of food aid in countries at the earliest warnings of famine, or tracking unemployment patterns to predict where violent extremism could emerge.

It’s important too UN watchers say to acknowledge and learn from the organisation’s successes, highlighting two major recent triumphs.

The first triumph is the nuclear agreement with Iran. Sometimes misinterpreted as an agreement between Iran and the United States, the accord is in fact between Iran and the UN, represented by the five permanent members of the security council plus Germany.

The second big triumph is the successful conclusion, after 15 years, of the Millennium Development Goals, which have underpinned the largest, longest, and most effective global poverty-reduction effort ever undertaken.

Welcome as these achievements are there is no escaping the need for the UN to do more in terms of reforming and reshaping it role. Last year in an analysis by the World Economic Forum, three areas were identified as priorities for the UN’s programme of change.

The first was a need for an increase in funding. Spending on all UN bodies and activities – from the Secretariat and the Security Council to peacekeeping operations, emergency responses to epidemics, and humanitarian operations for natural disasters, famines, and refugees – totalled roughly $45 billion in 2013, roughly $6 per person on the planet.

This, says the World Economic Forum, is not just a bargain, but also a significant underinvestment. The UN it says simply cannot get by on its current budget.

The second priority must be making the UN fit for the new age of sustainable development. Specifically, the UN needs to strengthen its expertise in areas such as ocean health, renewable energy systems, urban design, disease control, technological innovation, public-private partnerships, and peaceful cultural cooperation.

Last but not least the third major reform identified was the urgent need to address the problem of the UN’s governance. This should start with the security council, the composition of which no longer reflects global geopolitical realities, while its rotating seats policy likewise

does not adequately restore regional balance.

As Secretary General Ban Ki-moon steps down this year he leaves behind a UN under pressure and a daunting set of tasks for his successor. Inadequate as it the UN in so many ways, it does still matter.

This weekend the Syrian city of Aleppo continues to endure relentless airstrikes and the humanitarian crisis there deepens even further. The city’s remaining citizens continue to wait for the UN to save them from hell. Aleppo stands as a horrifyingly vivid reminder of the need for a better United Nations.