Allows shells to pass right by the crew without inflicting any damage, enabling an immediate counterattack. The unrealistic fragmentation effects of APCR rounds equally irritate me.

As far as i know all solid shots produce spall based on residual penetration after going through the last layer of armor. So the more penetration power is still left the more spall the shell creates.
If you want to make a suggestion for how it should be instead then you can create a suggestion in that section. Do note that for suggestions of that kind that is changing a very fundamental thing they require the suggestion to be quite detailed.
Before you create a suggestion you should read through their rules and guidelines. That section is also pre-moderated so a suggestion that doesn’t follow their rules and guidelines will not be accepted and won’t get published for other players to see.
A stun mechanic was proposed for official vote and rejected by the community.