I would recommend thief if you’re putting a focus on open world. They have insane mobility in regards to map completion, and their mechanic can make it to where they have no cooldown on their weapon skills (practice required, ofc). Their superior access to stealth also make a few puzzles easier on them in case they need to sneak past nasty mobs and such.
They have decent great DPS and superior focused DPS. They have a few rotations that reward the player for paying close attention to their target.
Dungeon wise thieves are highly accepted due to their near perma-blindness (depending on the monsters’ attack rate), and some paths make use of their stealth to brush past difficult content such as Arah paths, for example. They also bring projectile control in the form of Smokescreen and Dagger Storm.
Engineers are great, but for some reason have left a bad taste in players’ mouths. Open world they have great mobility due to true perma-swiftness and having quite a few gap closers (about-face techniques are well for more gap closing cheese). They also excel at hybrid damage so you could go condi, berserker, and even Sin gear works excellent for the class.
Dungeon wise, be prepared to press a lot of buttons as well as bring a non-condi build. For the most part as an enginner you’ll be expected to bring a bomb/nade build for max DPS as well as vuln stacking. The rotations on an Engi are intimidating at first but will just require a bit of practice. Utlity wise, Engi bring various field (most importantly: fire, water, and smoke), have a large amount of blast finishers, AoE healing, projectile control, and a few other things as well.
Personally, Engi’s can be very overwhelming at first due to high versatility, but they excel in the right hands.
