i don't agree that the gui looks similar to the currently established silverbull aesthetic. the icon has glowing cyan runes on stone, with gold features and turquoise ribbon. the wynncraft store silverbull section has squares of stone to display the information on the page. still pretty medieval-y. the gui, on the other hand, is not consistent with this imagery, it just superficially shares two of the colours, the gold (well, orange) and the turquoise, and none of the rest. if i was told it was silverbull themed without seeing it, i would imagine the stone and the runes and the gold features and the ribbons.
i also disagree with the idea that having predominantly beige, brown and grey cannot be interesting. your guys' work on the character info, ability tree and mastery tome gui is proof of that - it is interesting not because of the main colours but because of the shape, the imagery, how it's presented and the little details. this gui i feel is way too bold and salient and simplistic; it lacks the charm and uniqueness that the rest of the custom gui's have, instead seeming to go for big and attention-grabbing and blunt.
i also don't think the argument that wynn being supposedly a cartoonish medieval game factors well either. everything else in the game, from the resource pack to the npc skins to to the guis to the logo is drawn in a more or less medieval style. reinventing what wynncraft looks like when the current style is already so ingrained just seems like it would cause whiplash.
in terms of the chat tags, though, i think they look pretty good - my only real gripe is that for some ranks, the text seems to have too much saturation or contrast or something, just looks wrong.