When working with Sibelius-sounds adding instruments with their specific sounds is quite easy going and very comfortable. Also a lot of sound-libraries such like EastWest stuff can be handled easily with soundsets.
But very often there are no soundsets available for unique, rare or older sound-libs like Forest Kingdom, Colossus or ActionStrings.
Also when creating own sounds with NI Kontakt adding those to Sibelius can be a real nightmare.
I wish there would be a true midi-mapping which could be selected in the playback-config with the result that all preferred instruments set either in the preferred instruments table or in the instruments-panel itself will be ignored so that one could select the midi-channel and sound-engine in the mixer.
For now it snaps back to some settings useless for the given project, at least when reloading after a while.
Sibelius should be able to memorize what sounds in what engine were loaded (like all other programs)