I was hoping they would expand on Torghast-like tech. Like I know it sucked being forced to farm these for necessary items like legendaries, but after tuning/improvements were done and it became mostly optional I really enjoyed doing it for the challenge and to get the achievements/mounts/transmog.
If delivered differently I think it could make a nice hit, especially with good aesthetics of an expansion like Dragonflight instead of the current dark metal jailey areas that all look mostly the same.