My suggestion is to include the \tempo "Allegro" 4=160 type command in
the Rhythms section of the Learning Manual, since tempo is fundamental
to rhythm, and I didn't find it anywhere else in the learning manual;
I'd even put it as early as 1.2.1, along with Clef, Time Signature,
I agree. A simple example could be included in the same brief
style as the others between Time Signature and Clef in 1.2.1.
This would be easy to do.
etc., or at least in section 2.1. And, I'd also suggest it be put
somewhere more logical in the Notation Reference as well, since its
current location Under Staff Notation->Writing Parts is among the last
places I'd think to look to find tempo commands; maybe in section
1.2.3, Displaying Rhythms, alongside Time Signature etc.
I agree with this too. The Metronome marks section would be
better placed in 1.2.3 immediately after Time signature, but
the move would require some juggling with a number of snippets.
There are higher priority doc items, though.