What are some of the major stylistic nuances to address when performing Bach's music on the marimba?

I'm not sure if this is the sort of thing you're going after, but I'd mention the following regarding the performance of works by Bach (or other Baroque-era composers) on marimba:

- Studying baroque music is a great way to establish a strong foundation in one's playing, regarding phrasing: phrasing the shape of a melodic line, phrasing the meter, etc. These aspects of performance are often overlooked by younger (and even intermediate and beyond) mallet players, but the ability to phrase is something that will inform your study of other repertoire.

- Embellishments (appogiatura, turn, trill, etc.)- this is a significant element in Baroque performance, but it's often underutilized (or underappreciated) by mallet players. Get a copy of C.P.E. Bach's "Essay on the True Art of Playing Keyboard Instruments" (W.W. Norton & Company, New York), if only for his writings on the application of embellishments. It will help you both to apply the embellishments offered by the composer in the manuscript, and to add your own embellishments appropriately and tastefully.

- An obvious one: preparing a fugue on marimba is great training for implying/executing polyphonic textures - performing more than one voice simultaneously, and communicating that to the listener.