I would like to see the ability to control WHEN the coolant turns on and turns off.
In Mastercam, I had the ability to leave the coolant off, or turn it on as it reached the clearance plane or immediately after it changed tools (I guess for old machines with low pressure systems).
The same feature could easily be used to select high pressure or through spindle coolant.
This was done, per tool, in the tool library. It could also be set up as a default in the post processor checklist, when posting G code.
This should definitely be a feature.