Something I think should be added to the lower mid levels.
Add a one-time non-dungeon quest, bestowed by the person next to a popular F2P quest (I'm thinking Stormcleave), that awards a (character bound) Moderate Fortification item and triggers a tutorial (via the little in-game hints) about why Fortification is important to all characters, whether they are low-AC low-HP arcane casters, high-HP low-AC barbarians, or medium-HP high-AC 'defender' builds.