I have made it somewhat harder, you now will be attacked from two areas (from the rear as well as the front), your trading is restricted.
I have played it and it is hard, you must get your defences organised, unlike some other scenarios I believe in giving you a bit of a breather before the big assaults!
Use your time well, and most of all enjoy!
There is only one very narrow passage in which you can be attacked which makes it very easy to defend. All you gotta do is make a massive moat. I didn't do this since it takes out the fun, but made additional gatehouses stretching out from the main castle with traps between the attached gatehouses and smaller moats. There were very large armies, but they don't have a chance with the narrow passageway. I also had a pop of over 200 most of the game. I did like all the farmland and such, but the castle was prebuilt perfectly, so there wasn't much creativity on my part to win. The castle was a very good design however, and a masterpiece. The inability to make pitch ditches was a nice touch, but it still didn't make up the difference that the enemy could only attack you from one side.