A bad example - The Sparkle Hands (and almost all of the other 'lightning charges themed' items). Why would gloves which have a mention of some Yrre the Sparkstruck in the description casually wait for you in the fetid bog in the middle of nowhere? How does it connect with wooden woads and mud mephits nearby? Why is there a chest here in the first place?
Ground is super effective against electric, obviously. The fool took his magic items to one of the few places they wouldn't be of much help.
2. Class items are tied to class actions
A bad example: If I am not a bard, I have no use for Blazer of Benevolence, Cap of Curing, Boots of Brilliance. If I am not a barbarian, I have no use for Reason's Grasp. Those items are useless outside of their class and it makes getting them from enemies or treasure chest an irritating rather than rewarding experience.
A good example - Bloodguzzler Garb. Even if this item is barbarian themed, any class can make use of its effect. I can even build a mage armor melee dex-wizard around it. A very good design here.
I disagree with this. I don't want
all magic items to be class generic, especially if the items give out unique class-related abilities. It feels cool to get a magic item that's specifically geared toward and usable only by your class, and synergizes with those abilities.
Now, because this is a game and the DM can't tailor magic items for the party, I recognize that there's a chance we get many items that aren't relevant to our party composition. Perhaps Larian could, when we open a chest, check to see our party composition and only give us (or weight more heavily) items that match our classes..?