A computer can't really do this intuitively. Having two different systems to calculate hit chance would make it easier..
I mean, it would be better to have a more nuanced system for damage in general (i.e. different weapons more suited for different armors, etc), but I guess we are stuck with what D&D offers in this case, which is a fairly simplistic and limited system in general.
Still, there would be plenty of ways to "automate" this stuff. I.e. pick what type of "miss" you get according to how far from the target you went.
Possible examples:
if your roll would have it the naked target but it's his armor class that puts him above taking damage, you'll get a "clang" instead of a miss animation.
If you are in the range of 2 point from hitting someone with a shield, it's a shield block.
If it's a 1, you literally fumble and miss on your own, etc, etc.
That's about it for the suggestion.
Now the elephant in the room: I'm not sold AT ALL on the idea that this would be enough to make people satisfied with, say, not doing any damage for 4 rounds a row.
I'm not even saying that you should totally cheat the rolls, to be clear. It's just that I find questionable the idea that cosmetic variety would be enough.
