The League of Legends designers are considering ways to counter the power of shields that seems to be increasing with current items and even upcoming Keystone Runes.
While some champions have self-shields to protect themselves in solo lanes, the real issue that many players have pointed to recently is the power of supports to shield their teammates through a mixture of items, abilities, passives, and current runes. Along with shielding, healing is one of the two main benefits that a support can lend to their team, but with a way to cut healing already implemented through Grievous Wounds, some players feel that something's got to give with shields.
Riot Fearless, the design lead for League of Legends game systems, occasionally addresses players' questions on Tumblr about game mechanics and possible changes. One anonymous user recently asked referred to the shielding problem as a shield creep, or a gradual power increase that slowly builds up to being too impactful.
"How do you feel about the so called 'shield creep' in the recent meta after the Locket rework and introduction of the increase shield/healing stat?" the user asked, referring to the Locket of the Iron Solari item and the passives on some support items that further boost shielding and healing power.
Fearless responded to the question by saying that there did appear to be a need for some type of counter to prevalent shielding.
"We need release valves for excessive shielding," Fearless stated. "Talking about this lately, mostly around who most needs access to the ability to reduce/break/punish shielding."
Release valves have been a point of discussion in the past for troublesome parts of League, frequent healing being one of the most well-known. Grievous Wounds was the solution to healing, and it now seems that shielding may get the same treatment.
The release valve could involve a similar mechanic as Grievous Wounds where an item grants the ability to cut shielding power by damaging an enemy, but other options are a bit harder to speculate on. Creating a stat similar to armor penetration but for shield penetration instead might be one avenue, but those discussions will likely come later.