In this small alteration:
all roman factions are at war with each other, this may not last but it slows there expantion and seriously weakens them making for a more intresting game pontus, greek cities and macedon are currently allied to help beat of the romans and keep them strong every province has a high way, which is great for barbarians and horsemen, (sadly I havent changed the build list symbol so its the roman baracks, but this does not effect gameplay)
The greeks and seleucids have a greater starting fund as they always seem the weakest civilised groups (dont worry if your a neighbour of the seleucids because there begining infrastructure is still bad so they wont be making stacks of troops but it will help them catch up)
This works on Rome 1.5, I havent tested it on others make a copy of your imperial campaign and paste it in your campaign folder, usualy here
C:Program FilesThe Creative AssemblyRome - Total Wardataworldmapscampaign
(or where correct on your system)
then paste this into the newly created campaign (you can change the folder name)
If asked if you would like to replace file say 'Yes'