What ?Give the player a way to disable auto targeting for selected artillery turrets and wagons while still beeing able to use them for remote-controlled bombardment of hand-picked locations.
A simple checkmark labeled "Auto target biter bases" in the artillery's GUI could control, whether auto targeting is enabled (checked) or not (unchecked).
If you want to go extra crazy on this, the checkmark could instead be a dropdown labeled "Auto target:" allowing the selection of "Enemy bases" "Enemy bases and trops", "Biter bases", "Biter bases and troops", "Nothing" and select the corresponding behaviour for the artillery auto target logic.
Why ?Artillery is nice for automaticly keeping your lawn clean of biter bases as it is.
But used with the remote it is also good for quickly scouting ahead and removing biters from our freshly discovered oil and ore deposits.
On this occasions, having the artillery randomly waste shells on and atract hordes from biter bases that i do not actually care about right now, is inefficient and may attract biter hordes before the field camp construction is complete.
Also artillery auto targetting is much worse than me after a minute of training. So i would prefer to have the option to park my artillery train or turrets in the field and manually place the shots. I destroy three spawners/worms per unupgraded shot in average, where artillery auto targetting only frags one most of the time.
And i really like watching the shells hit the ground. That is easiest, when they only drop where i commanded them to.