I will begin this post as I have begun many of my posts since August 2016: In GW2.....
There are a number of abilities that can be unlocked by participating in the Mastery Points system. The way it works is, once you get to level 80 (the cap) you can still accumulate XP, but only if you have an active Mastery Track open that you're working on. These aren't hard to get, there are many of them (if you bought the Heart of Thorns expansion that is). As you look at the list of different abilities you might unlock, you can activate "working on this one" for the fist ability in the track, then any XP you get goes toward activating that skill unlock. To actually unlock the skill, you need to fill the XP bar AND spend a set number of Mastery Points. If you read the wiki, these Mastery Points, which are sort of the rate-limiting reagent in the system, can be acquired by doing a number of different tasks. Go to the hard-to-find place, do the mission and avoid the green stuff, etc. So you start yourself on the Mastery Track, you get the XP, and hopefully by the time you've filled the XP bar, you've got enough saved Mastery Points to unlock the thing you were trying to "Master", otherwise you need to get more Mastery Points somehow or else start working on a differnet Mastery Track so as to avoid "wasting" XP that you migth have gained otherwise.
Things I like about this system:
1. It gives me a tangible benefit to collecting Badge-type stuff beyond just the Pokemon ethos of "Gotta Catch `em All!" I'm not saying we need to actively try to recruit non-badge-hunters into the badge hunting fold, but giving players more reasons to do that content (get those badges) is not a bad thing. I mean if you're going ot have badge unlocks, making them valuable for more than just completeness can't be bad.
2. It provides game play experience that makes the game fun and playable post level cap.
3. It can be a thing to get some of the Mastery Points, like you have to keep trying at the task to get good at it before you get the MP. I like that. It adds replay-ability to the game. It's like I have to keep doing the one mission until I manage to figure out how to defeat the boss while dodging his large AoE attack such that I don't get touched by it even once and then I get that MP for "Avoid the Green Stuff" or whatever it is. Some others just require you to explore and find them, which is another cool activity, just exploration.
4. Some of the Mastery Points are earned by doing group raid content in the open world and as such give you a reason to do that content more than once too. Also, the unlocked Masteries can help you in that content. I, for example, recently unlocked "Nuhoch Stealth Detection" which allows me to keep hitting the Snipers even after they go invisible and "disappear", which is helpful.
R.S.O. of Phoenix Rising