Jon has lots to stay, starting with the Engineer profession's tool belt, which is a handy mechanic exclusive to the Engineer, and one that the GW2 developers felt had a lot of unused potential. "When we initially talked about the Engineer, only some of the heal and utility skills had corresponding tool belt skills, but as we spent more time with this profession -- especially testing for the Gamescom demo -- we started imagining a much cooler version of the Engineer's tool belt, where every slotted heal/utility skill had a tool belt counterpart," says Jon. In the end, this cooler version added 23 more skills to the Engineer's repertoire, which Jon details in the blog.
Engineer upgrades are only the tip of the iceberg, however. The GW2 developers acknowledged a long time ago that pets could use some tweaking, which they've been hard at work improving. The tl;dr version is that players will now have two aquatic and two terrestrial pet slots (amphibious pets can occupy either slot type). This gives Rangers a lot of flexibility within the dynamic combat style of Guild Wars 2 -- bringing in a new pet immediately when the current one is downed, for example. Rangers will also have much more control over their pets' behavior.
Pet skills and acquisition also have some big changes. Pets no longer evolve; but their levels match that of the player character, eliminating the need to spend time leveling pets. Pets have "family skills" according to animal type -- bears, drakes, felines, and so on -- as well as a unique skill for each species within a family.
Finally, if you're a fan of cross-profession combos, you're going to love the final part of this blog. Longtime fans know the "shooting an arrow through a fire wall" combo entirely too well by now, but Jon brings some new examples and some exciting new details of cross-profession combos. "Leaping Death Blossom through a Symbol of Faith will remove conditions from allies near your target. Stomp inside a Smoke Screen to cloak nearby allies. This is just a small sampling of what you can do with combos, and we leave it to you to find them all and combo to your heart's delight."
Jon goes on to give a detailed explanation of how the foundation of the system works, running down some pros and cons of development and balance. Just as Guild Wars 1's unique skill bar restrictions made for some amazing builds created by players, these combos in GW2 seem to be the logical next step into player-discovered efficiency and power.
We've given you plenty of details, but there are even more at the ArenaNet blog, so head there for the full scoop!