My examples will be HBO's Game of Thrones, a TV adaptation of George R. R. Martin's novels, and the anime Shingeki no Kyojin or Attack on Titan, an adaptation of Hajime Isayama's manga. There will be spoilers, some more and some less heavy, so if you don't wish to be spoiled, stop reading after the next three paragraphs. There is an ending chapter at the very bottom of this post as well, with no spoilers..
Series with strong, well-rounded support casts are usually viewed as good. Real characters around the main cast make the story feel more real, better somehow. It makes sense: it's nice have people instead of stock figures around. You see this in well written books as well - you find out about the people around the main character(s) as well, because they are interesting too: they're people, just like the protagonist.
Now, both Shingeki and GoT are notorious for killing people. Practically all of them. One might think this puts a damper on the well-rounded supporting cast, since they'll spend most of their tome dead. This is partially wronk. In the print versions (books and manga) this works rather well: you meet a character, they're fleshed out over tens or hundreds of pages, they develop a persona. When they are killed, you feel a loss for their passing. It's sort of like someone you know, and then they're dead. In the visualized versions, however, the supporting cast are just so much cannon fodder.
From an analytical viewpoint, I understand what's happening. GoT is supposed to be gruesome: the whole point of the "King Wars" is that everyone is just flesh and blood, and if you fail once, that's it. Shingeki, on the other hand, is supposed to be hopeless - human kind stand no chance against the titans. And as I said, in the written stories (Martin's books and, so I've heard, the Attack on Titan light novel) this works splendidly. The manga does an ok job at this. But the visualized media ends up feeling a bit slapstick.
BE WARNED: YOU ARE NOW ENTERING SPOILER ZONE
Sadly, these pieces do not stand up to their written counterparts. With Shingeki no Kyojin, the problem lies a bit in the writing: the characters feel stock. At the beginning it doesn't matter that much: Armin's squad at Trost, all of the nameless Guard members, even Marco's deaths seem to actually carry a bit of weight, but they feel kind of pointless. As the story progresses, however, it gets more and more ridiculous. The underlining of humanity's inability to fight the titans is made abundantly clear in the Expedition Beyond the Walls arc, where the Female Titan rips apart most of the Scout Legion. To drive the point home, she eventually rips apart most of the senior Scouts, Günther, Erd, Petra, and Auruo.
At this point, it trips over itself into the land of ridiculous. All of this is supposed to show the difference in power, but it feels needless. All we've learned during the anime about Captain Levi's squad is that they're supposed to be really good, then we see them do it for about 40 seconds, and then they die. The people dying could just as well be cardboard cut outs at this point, because everybody seems to die anyway. Both the characters and their deaths have lost their meaning, because the visual media doesn't have the time (or doesn't take the effort) to establish them.
The same problem lies with the Game of Thrones series. In the books, which are rather long, we get to know everybody rather well. In the series, people just end up dying one or two episodes up the road, with no real personality shown. As season three rolled about, a video was made that summarized the way people die in GoT rather well. While the event itself and the people that die in it are significant, it feels lackluster in the series, because it needs to chop up stuff so much that, again, everybody's dying all the time. Here is the video in question.
THERE BE NO MORE SPOILERS FROM THIS POINT ONWARDS
I like both of these series, but they just seem to be unable to build characters out visually, and end up the worse for it.
