Re:How do you review this sort of thing (Score 5, Informative)

Ah... the Goldberg Variations. There is something in it of divinity which the ear cannot distinguish...

Music notation is not really precise anyway. Interpretation is required for tempo indications, dynamic marks, phrasing, various inflection marks (e.g., exactly how long is "staccato"?), ornamentation and all sorts of other stuff.

Bach was more precise than his contemporaries in writing ornaments that he required - the aria of the Goldberg Variations is full of ornamentation - and he lamented the common practice of performers chucking in ornaments ad libitum. Even so, it's not always easy to see exactly what ornament is written (I have seen the E minor arpegiando in the first section of the aria notated as both descending and ascending in different editions because the handwritten copy is note easy to read). But he frequently didn't give any indication of tempo (and often when he did, the meaning has changed over time, e.g. a Baroque "presto" was different from a romantic one, and in any case Italian tempo indications are often also not just about tempo but also about affect. He certainly didn't give metronome markings, because the metronome was not invented until later.

Also, there is a lot assumed in music notation that is cultural.

Finally, the Goldberg Variations was written for harpsichord or clavichord, not for the piano. Both the harpsichord and clavichord afford the player less fine control over dynamics than the piano but the harpsichord allows a greater range of timbre because they often have various stops. So playing this music on the piano should rightly be considered as a transcription (which is not to criticise it in any way).