In various posts, it´s become clear that, during the Crisis of the Third Century, there were many rebellions and uprisings. Many of them occurred within the Roman Army and took the form of elevating usurper emperors, which never changed anything in the long run (and probably also wasn`t meant to).
Others didn`t, and they were bent on some sort of change (although of different kinds): the Agonistic Christians in North Africa, the Bucoli in Egypt, various "latronicia" in Italia, the Bagaudae in Gallia. Religious persecution, declining living standards and structural socioeconomic changes especially in the countryside (sliding towards the unfree colonate) were common roots, and, unsurprisingly, some items recurred on the agendas of the various rebel groups, e.g. land redistribution, debt cancellation, and the chance to follow their own religious rules undisturbed.
Being isolated from each other by space and time, lacking capable leadership and/or an overarching coherent framework, none of them achieved anything; the weakened Empire, although simultaneously faced with various external threats, too, still managed to hold them all down. Only a few decades later, religious freedom would be decreed from above, and another century later, the landholding Roman aristocracy lost most of their properties to invading Germanic tribes anyway - but those who had rebelled in the 3rd and 4th centuries (and before and after) would not benefit from that.
I am somewhat stuck with my timeline ("Res Novae Romanae"), that`s why I come to you with this question:
Let´s assume that several of the above groups, and more, rise more or less simultaneously, and that a part of the educated elite (both civic/urban and military) plays their vanguard, with one or two leading guys formulating a reform/revolution agenda with broad appeal to the OTL politically apathetic plebs (let´s think of Kleisthenes of Athens or the Gracchi as a historical antecedent/model).
- How far could a conspiratory network/confederacy/alliance realistically stretch, in terms of geography?
- Which places would be most likely to be rebel strongholds, which places would be least likely?
- How strong would a rebel alliance have to be to tip the balance of power in their favour and prevent a reconquest by the old establishment?
- If the rebellion / revolution is not put down, how long does it take to gain complete control over a cohesive territory?
- If the old elites manage to hold onto power somewhere, how will they adapt to the changed situation?