Hello.
TL,DR: Multiple artillery pieces extend duration of fire mission too much, and the player has to wait dumbfounded for many minutes after all life has perished. One unit (I counted 6 grenades over 30-45 sec) is good, but additional units should extend coverage (spread) or rate of fire, rather than duration.
I feel like it is counter-productive to have overlapping artillery coverage. (Many pieces of artillery in range to shoot to same location from different locations.)
What happens when many artillery units are in range: Fire mission duration extends. Of course if purpose of it would be to suppress enemies down it would be great, but it just basically happens to kill everything with few first grenades. They are very powerful, which IMO is good (When encountered mirelurk queen, 3 non-direct hits took it down on survival difficulty.), but when barrage keeps going on for many minutes at 10 x 10 meter area (from which all life has perished during few first hits) it just keeps player from advancing and moving there.
My suggestion is that overlapping artillery's fields of fire do not just extend duration of fire mission.
If it does: Add more coverage for barrage= More spread and effect.
Other idea would be to keep amount of shots (Lets assume each unit fires 6 grenades.) but increase rate of fire.
Does anyone else feel artillery is a good addition, but extensive coverage denies area of firefight / combat for too long?