problem

[MarcusAureliusAntoninus]

I have had a similar problem, and seen many similar. If it is the same problem, then it has to do with the fact that the settlements don't know how to revert to rebel. And in that case, assassinations won't work (I tried). In the "Rioting oddity" thread this is discused.

Try this suggestion:

There is an issue in RTW 1.2 (not sure if it's still in 1.5) where rebels won't spawn when the faction OWNING a settlement has no units recruitable in that settlement. The reason for this is that when a city revolts, it uses units that were recruitable by the owning faction.

An easy to implement workaround that I found a while back is to open up export_descr_buildings.txt and under the 'capabilities' section for EACH 'core_building' (ie Governor's Villa and so on) type the following:

recruit "rebel pantodapoi" 0

This will mean in the game, the building description would display 'Pantodapoi' but it won't appear in the recruitment window since only the 'slave' faction has ownership of it in export_descr_unit.txt. But when that settlement revolts, no matter who it revolts to they will get these Pantodapoi.

You could take it one step further and restrict the unit recruitment to specific areas (ie in the east the Pantodapoi will appear, while in Gaul some basic rebel-only Gallic units will appear), but that would require too much fiddling with hidden resources.

See if that solves your problem. If not, then there's something else that must be happening.