Your Campagin sounds funny. =)
I beat my Silvan Campagin yesterday after 276 Rounds.
But after 200 Rounds my Campagin was Hell on Middle Earth!
Gondor, Rohan, OotmM are destroyed, Noldor and Eriador had a hard Time vs. Isengard and the Dwarf+Dale Alliance were in a brutal War against Rhun.
When i finaly break down the Walls of Minas Morgul and the Black Gates, Harad attacks, holy

, the next 50 Rounds were full of epic Battles.
Around Turn 250 Isengard and Rhun also join the Anti Silvan Alliance and i lost over 10 Castles. =)
In Round 276 i was back, Mordor destroyed, over 40 Castles and Peace with Isengard and Rhun.
But Harad is still on a killing spree, so when i finished my Gondor Campaign... maybe... =)