@Randy
In version 2, with workbench, you can examine each entry in the arranger (each key you can set to 'happen' as the time bar scrolls past it.
They have an action associated with each key which is a belcanto phrase. Additional actions can be added to each key. They can be whatever belcanto you like.
You can also set up how the time bar moves with respect to the tempo (so lets just assume, for now, that it moves along at a 1/4 note rate in 4/4)
You could, as just one example, set up a 64 beat arranger. On the first beat set a tempo (120) and on the 32nd beat set another tempo (135). The tempo will then switch back and forth every 8 bars. Of course, you could also set a new tempo over the course of a few notes as a accelerando (and put a few in at the end to slow it down again before looping back to step 1)
You could also associate finely separated tempos with many keys and select them in a way that would look a lot like the MIDI CC charts you get in logic - The arranger would play tempos instead of notes.
So, there is a simple example.
Another (sillly) ideais to change tonics to shift the notes that are played (either in the arranger or in a recorder) - you could play one bar of a 12bar blues pattern in a recorder and use an arranger to shift it over the course of 12 bars to it's appropriate spot.
So, basically, any belcanto action you want to happen in the course of a piece can be attached to a key in the arrangers.