Can I request another setting in Playback options: Timing that sets the length of the last note of a slur?
Even better would be the ability to set different Timings for each instrumental group (ww, brass, strings).
You might be aware of this already, and it may not be exactly what you need, but you can select a slur and, from the properties panel, suppress playback. I find slurs in Note performer in the strings are very problematic, and this fixes playback for me.
Hi Steve,
This is very good and reasonable request! +1 here!
Probably in the future we will have more control over the playback of the Expressions and symbols in Dorico.
This one of the most important things that I’m missing from Overture 5.5… Global + Per symbol, per technique, per expression control…
You could easily, in a very musical way, make a piece to sound humanized and balanced with less tweaking.
At the current stage Dorico Pro provides “Suppress Playback” as the only per symbol, per expression playback feature.
Personally for me the Playback in Dorico is as important as the Writing and Engraving. As we all know in the real orchestra
everytime, every piece sounds differently, despite that on the sheet everything is the same.
I wish success to the team! 
Best regards,
Thurisaz