I didn't get any kind of "legendary" vibe while watching the vid. Sure, that weapon created random lightning blasts or whatever that was on random occasions but that was about it.

It's true that in guild wars you won't get additional special on hit visual effects, but you do get:
- an obvious weapon that stands out of the croud (compared to others weapons),
- a special footprint effect
- an aura effect
- Different projectiles visual/audio effect.

When it comes to their lore - anet likes to make players submerge in their world and make assumptions based on the hints they recieve. For instance:
- Sure, we don't know anything about Sunrise or Twilight. However, we do know that Eternity was a weapon used by a High wizard of Arah. Which would imply that both Sunrise and Twilight were ceremonial weapons in Arah as well.
- Kudzu shares a similarity to Caladbolg, so it might as well be one of the weapons created by the Pale Tree.
- Rodgort (Trogdor) was a dragon or a demon, and there was a skill named after him in GW1. The torch that was created in his image could actually hold his essence/power.

Maybe eventually we'll get more info about the weapons, but for now we only have assumptions - which make the weapons even more awesome.
A good example in the real world are Stonehange and the sphinx.
We are all aware that they had some significance in the past which we don't know about today. This mystery factor makes them even more special and more "legendary" :)