In my opinion actions, spells, gear etc. should be avoided which break important game rules.
In BG 3 I was more or less annoyed by the
- Strength elixirs (breaking ability mechanic)
- some Radiation and Reverberation items (Luminous Armor or Helmet of Acuity f.e., breaking attack and defense mechanics too effectively, and only for the player),
- Gloves of Dexterity or Amulet of Greater Health (breaking ability mechanic)
- Haste (out of HM breaking action economy)
- Tavern Brawler feat or Titanstring Bow (unbalancing abilites, especially together with the Strength items)
- Risky Ring (unbalancing risk and reward because the disadvantage never really counted for the player),
- Band of the Mystic Scoundrel (totally breaking action economy)
- easy double damage by a simple effect like Wet (breaking damage balance rules).
- medium armor without + Dex restriction (breaking ability and armor rules, making an whole armor class useless)
Some very good game items which give big advantages without breaking fundamental rules are ok on the other hand. For example I don't see the Knife of the Undermountain King as game breaking. The problem is more this (weird) rule that effects of weapons and shields also apply if the slot is not active.
I think skills of the classes coupled with coordinated use in the group and positioning should be the main element of combat, not special mighty items/gadgets. I did my first playthroughs (which for the main 3rd act was in Honour Mode) without even knowing of and caring for Reverberation, Radiating, Haste, Elixirs and so on. I had only items I found by chance and playing the main story, which were not very many. I was shocked how much easier the game was when I discovered the broken items and mechanics (by reading), and while even after that I barely ever used Haste and never Elixirs, I could not resist the beauty of Reverberation, Radiating Orbs etc. And then I had to install mods to increase difficulty. Such a wheel is a bit dump, isn't it?
