From what I understand in grim dawn usually character defenses correspond to character needs.
Kiting casters usually don’t have high defensive stats but instead rely on kiting, not getting hit and cooldown-based defensive measures. Instead the characters that fight close and have to facetank enemies (vit casters, retal) have higher defensive stats partially because they need them to live.
There are some builds that break that paradigm but no build breaks it as hard as pets. For reasons that I don’t understand pet gear is filled with physical resistance all over the place even on slots that typically can’t get the stat. This creates a weird a situation where the best kiting build in the game that does full damage even when running is also much tankier than the builds that have to stay in close quarters to deal damage. Pet builds combine convenience and ability of avoid hits of a caster with one of the highest achievable physres so even when they get hit they won’t die (unless the hit is happening in deeper shards way above what other builds can do).
It even came to a point when many people use pet gear (bysmiel trinkets, even bargol’s core) to get physical resistance they can’t otherwise obtain, this is a symptom that those items have overabundance of stats.
My suggestion is to change Physical Resistance on Beastcaller set, Bysmiel Trinkets Set into Pet physical resistance. Change physical resistance bonus on Overlord’s iron grim into pet physical resistance, remove physical resistance from Emboldening Presence and add Pet physical resistance to Primal Bond.
This change will make you care more about not getting hit for a kiting pet player and makes pets die less (resummoning them is more of an annoyance than an exciting mechanic, I feel like), so pet builds relying on those items become less hands-free in terms of running but get QoL convenience to compensate.
Now I can see that this change may feel like an overkill (pretty sure pet builds can comfortably do sr90 even after this changes, many of them don’t even use the items I listed).