Instead of having a item that goes through shields, or whatever riot said, how about this?
An item thats damage increases, or increases the users damage, the more shields an enemy receives within a time frame that also resets upon a new shield being introduced.
A more specific, but untested and unbalanced example would be this:
Passive - buckler buster: For every shield an enemy receives within 4 seconds of another shield, you deal an additional 33.3% damage to them (stacking 3 times up to 200%).
This would be a pretty good assassin item(s) who's passive keeps assassins functional in the lategame.
So it could look like these:
Diamond's edge Cost: 1200g Components: Longsword + Amp Tome + 415g Stats 20 damage (adaptive ap/ad [because you know riot is on this already]) Unique Passive -Buckler Buster: For every shield an enemy receives within 4 seconds of another shield, you deal an additional 10% damage to them (stacking 3 times up to 130%).
Glass Slicer
Cost: 3000g
Components: Dirk + Diamond's edge + 700g
Stats:
55 ad
18 Lethality
Unique (Melee Only) passive: Buckler Buster
For every shield an enemy receives within 4 seconds of another shield, you deal an additional 33.3% damage to them (stacking 3 times up to 200%).
Mind Breaker Cost: 3100g Components: NLR + Diamond's Edge + 650g Stats: 100 ap Unique passive: Buckler Buster For every shield an enemy receives within 4 seconds of another shield, you deal an additional 33.3% damage to them (stacking 3 times up to 200%).
So, in this case if someone gets shielded 4 times in 12 seconds, you deal 200% damage to them, but if they only get shielded once you don't get any bonus damage.
This should definitely not be an item that adcs can use because of the significant itemization they already have for dealing with tanks.
Mind you, these items are simply ideas for potential implementation. I don't think they're very good or should be implemented as is, but we can use them as a launch point onto the real topic which is how we should implement shield countering mechanics.