I thought this was a nice ranking!

Spoiler: mastery xp potions are worth it..... If you don't use the potion but vendor it for 1g.

The new legendary armor set is planned for release in the second major update following the expansion’s launch. You’ll be able to begin working toward it on August 22, though—crucial components will be available to acquire, and you’ll be able to start training your Astral Ward Masteries to unlock crafting recipes. Part of the necessary steps for completing your legendary armor will be completing the Astral Ward and Rift Hunter’s armor collections.

This is from the blog post on the gw2 website.

Nope, not yet. Only build templates

That's a great place to spend your time!