This weight/resistance change to shields was not well thought out. On the surface, it's a buff, but this is the reality:
-Small changes in shield weight have a huge impact on crushthrough resistance and block stun resistance, and now even the peasant Maul will usually crush through most shields
-Even relatively light weapons like the Morningstar and Great Long Axe will now block stun most shields on held attacks
The resistance buff was obviously implemented to mitigate bolt penetration, and the secondary consequence is increased shield durability (which no one really wanted). The problem with shields isn't that they break, it's that between crushthrough, block stun, kicks, and the crappy lateral coverage (against both melee and ranged), they rarely even get damaged.
Here's my suggestions:
-Revert to the old shield weight/resistance values
-Make shield skill reduce the EFFECTIVE weight of shields for run speed/acceleration by ~1 kg/skill
-Make shield skill increase bolt penetration resistance
-Make shield skill increase crushthrough resistance
-Make shield skill increase the shield's lateral coverage against both melee and ranged