To be sure, an adjustable time-delay device would be a marvelous feature on the CT's. Personally I would not like to try getting that past UL.
In my shop my primary Kapex is bolted in place and plugged into a dedicated 120v 20a outlet. The companion CT22 is the one that goes with me into the field. It also has a dedicated 120v 20a outlet that is switched. I have not had any problems letting the vac suck between cuts, but if there will be a wait, I turn off that switch.
Now you have gotten me thinking about using an available dust collection relay, which functions like the CT auto circuit. There is no reason why the Kapex cannot activate the DC relay. Maybe one exists with a time-delay?
When I use my other Kapex in the field with the same CT22, I hook it up with a 36mm AS hose and using the outlet on the CT22. To clear the hose I blip the Kapex trigger. I learned to do that from my Festool dealer who had just attended Kapex dealer class. As far as I can tell this does not harm the Kapex. I agree it is important that the saw blade be still before lifting it clear of the work. I often do my blipping of the triger after the blade is clear of the cut wood.