This question comes up from time to time, and I understand why the abstraction has been made, but I have to admit it still feels like an awkward solution, even after all these years. Targets moving erratically at high speed really are difficult to hit with shellfire, and high speed ships really did chase shell splashes in order try and dodge enemy shellfire. A model which calculated time of flight to a predicted stationary impact point, and then applied dispersion around that point (to simulate all the accumulated errors of the targeting process and mechanical systems) would come closer to actual shellfire behaviour, without the awkward compromise of 'sticky' shells. It would help grant high-speed targets the advantages they really had.
However, if such a system were implemented, the current ability to see the incoming shells from the moment they are fired (and to be able to plot exactly where they're going) would make it liable to abuse. I wonder if it would be worth removing some of the shellfire graphics for enemy shots?
Enemy Medium and Large Calibre Guns
A firing gun system of medium or large calibre that is spotted by optical sensors would briefly display the current gunfire graphics, but the shell graphics would fade out after a very short distance, within a second or so.
No shellfire graphics would be displayed while the shell is in flight.
Shell-splashes would be displayed at the actual point of impact, like bomb bursts currently are.
This would let the player tell that a system is shooting, and vaguely in what direction, but they wouldn't know precisely where the shells are going, or exactly when they'll hit, or even which of their units is the specific target. If they want to try and dodge they can, but not in a reliable video-gamey way. If they can't actually see the gun system (artillery behind a hill, etc.) then they would only see the shell-splashes/impacts hitting around them. The player can currently spot hidden artillery batteries with perfect accuracy the moment they open fire, just by watching the shellfire graphics. This has had a major impact on several littoral scenarios (several of Gunner98's Fury series come to mind), and it would be an improvement if this was not possible.
Enemy Small Calibre Guns
Short-ranged small calibre weapons would retain the current graphics system.
These are typically tracer-firing direct-fire autocannons and MGs, where the stream of gunfire is often visible, and the ranges are so short that dodging is not an issue.
All friendly guns would retain the current graphics system.
Although the player theoretically shouldn't see his outgoing arty fire (except night-time RAP/BB), keeping the graphics helps the player manage his gunfire, so I think it would make sense as a play aide.
Some of these changes (particularly not seeing enemy medium and large shots in flight) might be helpful even if the 'sticky' shots were retained.
Anyway, just musing out loud. It's easy to make proposals when I don't have to do any work!