The 2014 reboot is a pretty big letdown because it largely avoids all the strong aspects of the original game in favor ip recognition.

The original Thief would largely be considered an immersive sim whereas Dishonored is a very well fleshed out stealth game with masterful vertical level design. Prey (2017) feels like a great mash-up of both games. I'd put the original Deus Ex and Human Revolution in there as well, though they also include rpg elements.

Prey’s closest ancestor, by a mile, is System Shock, I’d say.

Prey was so good too!