Ive seen some posts in the past about about this but no concrete stance on whether or not this will be worked on…
Dynamic KML layers (without having to edit the URL via the app definition):
a) KML field as a formula to lets us build the source url
**OR
**
b) shorten the cache time in a way so that we can use Drive hosted KML with network links or Google MyMaps links directly that shows updates quicker (kml seems to cache from 30 to 60 minutes at the moment)