Before Saturday's United Nations summit on Syria, some supporters of the country's opposition had their own plan – of sorts – to stop the unfolding catastrophe. It ignored the ongoing high-stakes diplomacy and any other talk of internationally brokered peace. All-out war, said activists, exiles and guerrillas alike, was now the only way to bring an end to the chaos in Syria.

Talking had done nothing but allow the Syrian regime to buy time and consolidate, the dissidents said. After almost 16 months' fighting in town squares and on battlefields, it was time to follow through with a momentum that many Syrians in southern Turkey and border areas controlled by rebel forces now feel is with them.

"There is no peace and there is no plan," said Ahmed Julak, 39, from a hospital bed in the southern Turkish city of Antakya, where he is recovering from a broken leg he sustained while smuggling ammunition into Syria.

"Nobody listened to Kofi Annan [whose plan to demand that both sides to step back from the brink has been stillborn since it was unveiled in April]. Not the regime, and not us. There is no dealing with these people, and that is the truth. And what is a transitional government?" he said, dismissing talk of an internationally backed administration to ease Syria free from autocracy and away from the spectre of war.

"If Assad stays or goes is not the problem. It's the regime that needs to go. If that doesn't happen, then no reasonable person can say there has been progress."

Many opposition followers believe Syrian leader Bashar al-Assad is merely a figurehead who Russia could sacrifice as a sign of compromise to the US and Europe, allowing other regime figures to remain entrenched and maintain the status quo. Others dismissed the significance of the UN gathering with a wave of the hand. "We have better things to focus on," said Houda Idris, an exile from the Syrian port city of Lattakia. "It is getting rid of Bashar and his mafia."

One man, recovering in hospital from a bullet wound to his kidney, said talks could never advance while Russia held most of the negotiating trump cards. "Impossible," he said, as he tried in vain to lift his emaciated frame to press home his point. "We will finish what we started."

Despite an influx of light weapons and an increase in defections from regime security forces, the means to force change still seem limited among the opposition, whose fighters are paying a heavy toll most days and whose backers admit to being fatigued by the relentless upheaval with no end in sight.

In the Syrian village of Qatma, not far from the Turkish border, a family from the town of Houla, where a massacre widely blamed on regime backers took place in late May, has taken refuge.

Mohammed Khiari, a defector, was in the nearby village of Taldou when men who he and others insist were members of the pro-Assad militia, the Shabiha, launched a bloody raid that killed more than 100 people, most of them women and children. He has been in Qatma since the massacre happened, along with defectors and their families from other parts of Syria, all of who seem to have similar stories of depravity and suffering.

"I've seen the face of this regime, because I was one of their soldiers," Khiari said, displaying his military identification which listed him as an officer. "I know what needs to be done to get rid of them. Negotiations to them are a chance to stall. And they show weakness. There is nothing left to do except fight. And we will meet our challenges."

The defectors sit each night on concrete floors in improvised meeting rooms to discuss how to organise what essentially remains a grassroots uprising that has recently taken on an international dimension.

And in recent weeks a new theme has crept into their discussions. Where basics such as supply lines and evacuations to Turkey once dominated, a new dialogue is taking place – how to prepare for life after Assad and what sort of society might rise from the ruins.

All of the men here have fought against the regime. All have lost family members. How to win justice for the dead, maimed and imprisoned in post-Assad Syria is now central to an emerging internal discussion. Vengeance is a common theme in all the regime hubs; meeting rooms like these, which dot the country – hospitals, refugee camps and frugal, cramped apartments in Turkey that often house dozens of family members.

"I'm not going to say I'm speaking for a grieving mother," said Idris inside her small flat in Antakya, where she now lives with her two daughters. "But the feeling of loss is very real and so is the need to do something about it. Blood brings blood. The people will take revenge. I'm not going to pretend that they won't."

Some war-scarred guerrillas, such as Houla exile Mohammed Khiari, are clearly conflicted by the issue of how to win redress.

"I know personally one of the officers who came with the Shabiha that day. He was responsible and I know where to find him.

"It is better to take him to a court, an international court, and to put him on trial, but this will take a long time and we don't know whether it's possible. Revenge is a real issue, of course it is. But we must find appropriate ways to deal with these issues."

Outside a refugee camp in southern Turkey, Abu Najib, who fled from the town of Jisr al-Shughour two months ago, said how to deal with life after the Assad regime is a difficult issue – almost as difficult as forcing the ruling clan to leave.

"So many people have died and we won't accept that he and the people around him led us all into this crisis. There will be a price to pay for this, but it should be through a court."

A second man, Abu Mohammed, spoke up: "In Yugoslavia the regime ran away when it all ended. It will probably be like that here too. There will be some who stay and they will be dealt with. "But look at the international [tribunal] for that crisis. It is still dealing with the issues many years later. Unless Bashar and his gang face war crime charges, the people will never be satisfied."

Where the UN and the international community may have been seen as ponderous in the Balkans, they are viewed in a worse light through a Syrian opposition lens – impotent.

"What they are talking about [in Geneva] is meaningless," said Idris. "It won't change things."