Even when you put aside all thoughts of sales, videos, chart positions etc, this is still an astounding, genius album. The production values are incredible, the melodies memorable, Michael's vocals and personality arguably rarely better expressed. Thriller will never be "just another" high-selling pop album to me, even amid all of the revisionism we've had from various commentators since.
This and Purple Rain are probably the two defining achievements of pop music during the '80s. I grew up with this album, and it is probably more responsible than any other work of music for igniting my love of music in the first place.
Timeless!! Imagine if this album was released during a time like now where there is HUGE influence of the popularity of music on social media and the internet. Or imagine being a teen when this came out, MJ even had a huge influence on fashion during this era.