Agree that the strategy you found is a bit embarrassing for the designer, it should have been found in QA if nothing else, and balanced out. On the other hand, I find the scenario quite enjoyable, with various routes to try out (go after Poland, go after France, try to reach Constantinople, or Iberia), and wouldn't get too hung up on that one particular route is broken. I think scenarios are not only meant to be beaten, it also gives a different flavor and more well defined historical setting than a general game of civ. I also enjoyed the Macedonia scenario a lot, as it challenged me to play super aggressive which widened my general warring skills. Personally I'd love to see more historical scenarios, like the Macedonia, Viking or Polish scenarios.