Here is a list of every patch released since launch
on the official site. Most of what's listed is temporary content.
The wiki also has an archive of all patch notes
I don't know of any really dramatic changes to engineer or mesmer, but here's a summary of new things:
- Magic Find is no longer a stat that's available on gear. If you had anything with Magic Find, you have to double-click it and pick a new stat array. Salvaging blues and greens will sometimes give you essences of luck, which you can double-click to increase your account-wide Magic Find stat.
- Earning achievement points will grant you a chest full of stuff, with a new chest every 500 points. You'll get one chest per day until you've reached your total.
- Each unique world boss will give you a guaranteed rare once per day. They're a little more difficult now, and they have a fifteen-minute timer. Except Tequatl, who is really
hard. Don't expect to beat him without organizing about a hundred people over voice chat.
- All champion-level bosses drop a guaranteed chest. Champion-farming trains typically form in Queensdale and northwest Frostgorge Sound (starting at Drakkar Waypoint).
- Dungeon loot has been changed so that it's less profitable to run one quick path over and over (i.e. CoF p1), and more profitable to several different paths. As you've noticed, there's an in-game LFG tool.
- Scarlet Briar is the new diabolus ex nihilo
. Every few hours, she and her minions will invade a zone for 45 minutes, which turns into a massive farming run. This month, Twilight Arbor Forward/Up path has been replaced with a new, much more difficult path focused on breaking into her facility.
- If you have access to a large guild, you can take part in guild missions - bounties (finding and killing bosses), treks (finding locations), puzzles (group jumping puzzles), rushes (obstacle courses), and challenges (group events) - to earn guild commendations. They can be used to buy, among other things, new ascended trinkets.
- The weapon-crafting professions - Weaponsmith, Huntsman, and Artificer - have been extended from rank 400 to 500 so that you can craft ascended weapons.
I'm probably forgetting some things, but those are the major permanent additions off the top of my head.