>Reposting from a leftypol thread on Berserk:
Berserk has flaws, yes, but anything so ambitious is bound to, and none of them come anywhere close to detracting from its well deserved status as a masterpiece. Berserk, though very definitely seinen, does have some small shonen trappings such as Isidro, Schierke, and (perhaps most divisively) Puck, as well as an intermittent stream of puerile jokes, and (I'll get into this later) its edginess, but even if overused at times these serve to expand the range of the story, rather than allowing itself to become too po-faced to feel believable (like FotNS, for instance) without feeling clumsy (like many of FMA's gags).
All of the characters evolve repeatedly and massively over the course of the story, except for Griffith, which drives some of the prime themes; about greatness, dependence on or independence from others, having goals versus merely living, the nature of the human psyche, and of human culture through the lens of human imagination. The fights and battles, while they make up the bulk of pagecount, many of the pivotal moments, and are gripping material, are also accessory to development that occurs while characters travel, meditate, and converse. Perhaps equally important to characters and events in the story, is the world and the increasingly strange things that fill it; a land that is at once wild and brutal even before Fantasia or Eclipse, then increasing peeks into the world of the astral are conceptualized and realized on paper by Miura with an imaginative serenity and nightmarishness matched by few artists.
As to a decline in quality? That is a common opinion, and one I would agree with to a limited extent, especially post-boat. But (assuming this isn't bait, which it probably is) your placing it at the Golden Age arc is unusual even for cynics, when the most popular arc (both at the time, and in retrospect for most discussions I see today from the middlebrow "Star Wars peaked w/ ep. V" crowd) was Lost Children. As for the expansion of the cast, it was necessary to buttress themes of personal healing and trust for Guts, similarly to what happened in the Golden Age, but with the added point of his learning to build up the people he surrounds himself with to become his equals, and attempt to secure his victories in some lasting way.
Now, as to edginess. I named Berserk as an example of something that has depraved content without feeling trashy not because it uses that content for some purpose (which it does), but because it is thematically unapologetic about it. For instance, as visceral and ruthless as some of the content in FMA, Monster, Now and Then Here and There, and Crest of the Stars is, without being trashy/edgy either, they included such content specifically to condemn the behavior that leads to it, pointing toward a future where it can be stopped, as the overall tone of those anime was distinctly, er... Moralfag-y. There's nothing wrong with that, but it is an easier and more appealing type of story to write. Berserk uses extreme content to paint a portrait of characters, situations, and worlds that could not be adequately realized with more restraint, not just to offer moral commentary or judgement on them, but sheerly to portray them for their own sake. In this respect, I would describe Baccano! and Garden of Sinners as similar to Berserk.