I was just musing about our inability to recruit a solo trombone and realised that our problems would be solved over night if the contesting rules allowed the use of the valved variety.
Many jazz musicians on the valve version make sounds just about indistinguishable from the slide so there should be little loss of tone colour. Glissandi are all but confined to the 'novelty' numbers so no real problem there.
So why not? Bring on the valve twiddling trombonists I say!