Actually I would prefer a larger DVD collection of just Trombones - if VSL could really nail it. I would be willing to pay the 'full collection' pricing if it hits the mark.
There are so many types of articulations that are specific to Trombone, solo and ensemble, that (certainly depending on VSL's technology and approach) would necessarily need to be produced.
I would think that they would need to really isolate their attention and creativity on this single instrument. Maybe the Vienna Instrument software itself would need to be futher developed in order for this to be done. Timing of the change and develpment of tone would need to be adjustable to fit specific phrases of your composition. Timing of Glisses and Rips would also need to be adjustable.
This much forward-looking development might need to be underwritten by the production of a larger DVD collection.
Imagine, if you will, clicking on the VI within a VE Pro that reveals a glorious, lively instrument that always produces the sonic effect you would want for a trombone or an ensemble of trombones. Imagine how much easier and exciting that would make your pieces that use brass.