I don't see this being discussed anywhere on the www
How come? It's an absolute beauty and it demonstrates Bach's genius even at his early age (he wrote this when he was around 20!)
It was composed after Reincken's Hortus Musicus' first five movements (the first movement of the original piece is broken down into 3 movements by Bach), but JS actually composed first 3 mov'ts almost from scratch, citing only a few basic motives, while the other 4 mov'ts are arrangements with added counterpoints.
Adagio should be played slower imo