To attract players to do events (which I mostly evade at my current level, because I don’t want to wander from my destination or spend too much time, and they provide so small rewards) there should be rewards like as for mission story books in GW1.
Here should be separate books for regions and/or zones, and content should be hidden (like ?) until you complete event.
And when you complete an event, empty ? line will be filled with event name and rank.
When you fill whole book (probably with rating silver or gold) these books can be exchanged, for example, for unique weapon or armor skins, or something else (maybe related to that region).
There should be wide and various rewards selection, so player will be always motivated to do events (and not skip them after he tried them once, as it now).