"Why should you be able to survive archer spam"
Basically archery has no hard counter. I think if a player is wearing plate only bodkin arrows and steel bolts from a heavy crossbow should harm them.
Throwing damage is a different story
The whole story with counters doesn't work in cRPG. If you have a game with a rock-paper-scissors-system, it has been constructed around that idea. It doesn't work on a game like M&B which was constructed around medieval combat, which was not about fairness, it was about being the shotgun in a rock-paper-scissors-system.
Thus the argumentation of one class having a hard counter and others not is not applicable. Least classes have a hard counter, and when it comes to one it's usually the horse archer. All the other classes are weaker or stronger against another, but it's not like you can say there would be a general meta-balance for classes. It just doesn't exist.
The range spam is a story for itself, but trying to find a way to be immune against ranged damage is like taking out the class of the game, and thus not a solution.