My overall impression of this expansion: Awesome!!

Rollout

You know, for such a significant release, I think the rollout has gone rather well (at least from the experience I've had). Yes, there have been some bugs, instability, and disconnect issues. But compared to some of the major releases in the past, this one has gone well. And I think you've stepped up your communication to your players about what's going on when there is an issue, so kudos to you on that. I would suspect that the people demanding compensation for these initial "burn in" problems do not have several decades of software development/release experience under their belts (I do) -- so from my point of view, your efforts in making this rollout as smooth as possible have definitely been noticed, and appreciated.

Zone design

The zones are beautiful. Anet, your art department has once again surpassed my expectations. The detail in many of the textures is amazing. The colors are vibrant. There is a lot of variety in the zone environments: snow, tropical, (of course) desert, marsh, rocky, quicksand, poison sand, caverns, etc. Simply fantastic. There is enough verticality to make the zones interesting, but not so much that the mini map becomes useless; you don't need to spend a huge amount of time looking for how to get somewhere and you can play the game instead of struggling with the map (kudos for listening to feedback on HoT). The way that the zones are designed to integrate the behavior of the mounts is a true achievement. When it was advertised that mounts would be integral into the zones, you really delivered on that -- without overdoing it. And the sheer size of the new maps (even taking into account the mounts) is incredible.

Zone encounters

The new creatures in the zones are interesting and fun to fight. I like that there is a mix of density and difficulty throughout the maps. I think you have achieved a good balance of places where getting through all the enemies is a challenge, with places that you don't have to be on your guard so much and can more easily enjoy exploring and take in the scenery. I really like what you've done with the Bounty system. It reminds me of map events, but rather than have them all gated behind completion of a meta event, or tied to the time of day, we can start them whenever we want. This is great. I'm hoping we'll see more things that can be started on-demand, while letting the entire map join in. And using this system to add some "current events" will make them easy to find, and they won't get forgotten as easily when more are added. I think you've incorporated much of the feedback regarding tying map state to events/activities into this design. Applause!

Story

The story was a good length (13 chapters is just right for my attention span). The story arc itself was interesting and it was cohesive from chapter to chapter. The ending of the story left just enough intrigue for upcoming Living World episodes, without going over the top. The way story completion takes you throughout the new zones was well done. I liked that there were a number of tasks that were somewhat puzzle-like throughout the story, and everything wasn't just a battle. On the down-side, some of the dialog segments are soooooo long that when having to replay that section, I went to a browser to read something while waiting for it to make it past that. [suggestion for the future -- enable dialog-skipping after going through it once]. Also, in the final three chapters, I think the boss fights were unnecessarily difficult, and (for me), they took away from the overall enjoyment/immersion of the story. I think they are interesting fights, but I think it would be much better to have fights of that difficulty level available as "challenge modes" connected to achievements. I also think that some of the chapters are a bit too long and should have been split into smaller pieces -- don't forget that we can't pause the chapter; if we get disconnected or need to step away, we need to restart the whole thing over.

Mounts

Fantastic! Incredible! Stupendous! I thought gliding was going to be tough to beat, and mounts might end up being a lackluster facsimile. I was so wrong! Each of the mounts has a totally different flavor to it and they complement each other exceptionally well. The mounts themselves introduce a layer of fun into the game, and they are so much more than a means to speed up travel. The way the zones have been designed to make use of the different mounts' abilities is great -- especially having to return to the earlier zones when mounts from later zones have been acquired to get to certain locations. I'm hoping that we'll see additional ways to customize their behaviors/looks in the future. There are so many possibilities. Compared to mounts/vehicles I've used in other games: you've taken this to a completely different level.

Masteries

The mastery line groupings around individual mounts is a great idea. It really lets us pick and choose how we want to evolve each of the different mount types. This is a welcome reminder of the "play your way" game philosophy. I still have a lot of mastery points to collect, but so far, I'm finding them at a good difficulty level and mix of fight/commune/puzzle/etc. Now that we've have three completely different groupings of masteries (Tyria, HoT, PoF), I think the basic concept of "horizontal progression" is going to be an ongoing success. And letting us use the new capabilities we get from masteries in the older areas of the world makes them even more enjoyable (I'm sure there's a lot of work behind the scenes to enable this).

New Specializations

I haven't played much besides Weaver so far, and I'm finding that it's going to take a bit of practice to learn how to play this. It feels very different from base Elementalist and Tempest. But adding something new that needs exploring is the whole point, right? I read an article somewhere that some of the design philosophy behind the new elites specs was to make them feel almost like new professions, without the overhead/bulk of actually having an entire new set of professions. Based on my experience so far, you've delivered on that. From what some of my guildmates are saying about the new specs for other professions, they're having lots of fun with them, so I'm looking forward to exploring more of the new elites, as time allows. One thing seems clear: there's quite a bit to discover here.

Summary

While I think there are a few things that could be better (and since that's subjective, there always will be), overall: great expansion. It really feels to me like you've taken much of the feedback you've been getting seriously, and have incorporated that into PoF's design. I think that the higher-level players might enjoy the challenge level of HoT more, but for folks like me who aren't ever going to be competitive gamers but still don't live on auto-attack either, PoF has the right blend of challenge and fun. Well done!