Tuplet number horizontal placement in 6.2.10

That would be a great option to have, especially after seeing many examples of this in bona fide publications.

Regarding the conditions required for the bracket to appear, it would be nice to have an option to omit the bracket in a beamed group when the separations are already explicit (different rhythm value or secondary beam split), like here (Ravel, Durand)

or here (Chopin, Wiener Urtext)

These figures in Dorico with the “only when necessary” option:

That said, the team surely has bigger priorities — and I created a shortcut to hide tuplet brackets anyway, so it’s not really an issue on my end!

I am not sure that this answers your question, but the tuplet number was generally placed on the note head side until at least the end of the 19th century. One will see this in the Breitkopf and Haertel complete works of Brahms edition (1926-1927), for example.

Apparently, the number was felt to be more visible nearer the notes. I myself think that editions of music from this period look more natural when the original notational style is adhered to.