I request a way to swing 16th notes in playback. Currently the only way to do this is to change the time signature to an 8 on the bottom, but this causes two issues: (1) The beaming is not correct (breaks 16th notes into groups of twos instead of 4s). You can rebeam to a different time signature, but this is cumbersome to do repeatedly throughout the composing/arranging/editing process. (2) If the time signature has 8 on the bottom, there are twice as many slashes in slash notation (so 8/8 has 8 slashes in a measure instead of 4). You can edit the staff to allow it to have an independent time signature, but this is also cumbersome and creates other issues--especially if, for example, the entire jazz band needs slash notation during a solo section.
This used to be possible with the tempo tool, but now there does not appear to be a way to make the playback sound correct.