My problem with the Seleucids is that in RTR (the mod I play) the Seleucid Empire starts with 30(!) provinces, and is impossible to manage at first. One time I pulled all my troops and generals back to Asia Minor (now Turkey) and let the Far East Revolt. Pontus and that part of the Ptolmaic Empire fell after several decades of rebuilding, Greece and Macedonia shortly afterwards, and the Thracians and Illyrians didnt stand a chance. The Sarmtians shredded my armies with horse archers though... At this point I had 32 provinces - back to where I had started! However I also owned some of the richest provinces in the game, and has the best army and navy.