I tried to classify the first page of bug reports, to put that system to the test:
So there's quite a few that I wouldn't be sure how to classify, and probably some cases that are debatable, maybe we should all try and see how many times we agree
- shops quality text not appearing: user interface
- enemy spells launch PC in the air: magic&effects, physics&movement?
- dungeon map zoom and TAB key: user interface
- gauges not updated upon level up: user interface
- casting some spells while casting some spells: magic&effects, user interface?
- radius of touch spells: magic&effects
- sleeplessness victim turns hostile: quest system&quests
- modded soundclips not preloaded: catch all, mod system?
- stuck on broken floor: physics&movement
- duel quest bug: quest system&quests
- protect honored mage quest last 24 hours: quest system&quests
- protect honored mage reward item always fortitute on held: quest system&quests
- protect honored mage random guild: quest system&quests
- spells don't tick during rest: magic&effects, formulas&mechanics?
- letters don't appear on first use: quest system&quests, user interface?
- cloaks rendered behind robes: user interface
- "cast when held" on unequippable items: magic&effects, formulas&mechanics?
- revolving door: catch all, physics&movement
- paralyzation doesn't interrupt climbing: magic&effects, physics&movement?
- "guard the mages guild" enemies not spawning: quest system&quests
- town npcs flickering: catch all
- knight order quest "the princess": quest system&quests
- teleport to dungeon retains music: catch all, user interface?
Not sure if that can be helped with classifications; tagging would be a bit more flexible, but that doesn't look like an option with just forums.
Hope it helps.