And we wouldn’t have a need for a situation like in Game of Thrones where all the soldiers are placed outside their castle, in front of their trench.I don't think guarding the drawbridge while it's raising would be a reason to have fortifications. Minas Tirith has a tower, so the Elves there are watching for the enemy and would raise the drawbridges before the army arrives. A drawbridge does not need to be fully raised to prevent enemies from crossing it. Moreover, staying on the wrong side of a drawbridge to guard it while it raises would be pretty much suicidal. It would make much more sense to retreat to the main fortress before the bridge raises.