How likely is it that any "splintering" would lead to a more moderate replacement government.
Sure it's more likely to be a more extreme, hard line government. They have all the levers of power - the law has already been changed to make it easier to crack down on “infiltrators and spies”
Again, from the BBC
While attention remains fixed on the US-brokered ceasefire between Iran and Israel, reports from inside Iran suggest a growing climate of fear and repression. As the fighting subsides, analysts and activists warn, Tehran may move swiftly to reassert control at home, especially after Israel’s apparent success in infiltrating Iran’s security apparatus.
The scale of those intelligence breaches has triggered widespread paranoia within Iran’s ruling circles. Today, the prosecutor of Kermanshah province announced that 115 people have been arrested for “disturbing security”. That includes a European citizen charged with espionage.
Hamidreza Karimi said “a small number” of the detainees face spying accusations, while most are accused of “propaganda against the system.” At least three people have been executed in recent days. Dozens more have been detained across multiple cities on similar charges, often linked to social media activity or suspected espionage.
A spokesperson for the country's judiciary says Iran’s parliament has eased legal restrictions on prosecuting espionage, allowing authorities to punish “infiltrators and spies” more swiftly and severely. “Under the previous law,” he says, “many of those arrested during the war with Israel could not have been tried. Now the parliament has opened our hands to deliver exemplary punishments.”