Guild Wars 2

I dont fully understand the new hero points system. Ill figure it out when the time comes. My question is, is there any compelling reason to squeeze in total world completion now vs after HOT comes out? I have a level 80 necro with about 20% world completion, and with only key skillls and traits unlocked. Will I lose my skills? Will it be harder later on? Thanks

Aside from gaining all the extra hero points:

• You gain rewards based on the level of the map, so some will give you two exotic weapons
• You will have all the Waypoitns for future living world/ event travel
• It is still needed should you get a precursors…
  *…. and since precursors are going to be a collection it will be easier to make a legendary once the expac comes out