Yeah, I also don't think it would be impossible to adapt Homestuck as a cartoon. A lot of the appeal of Homestuck is the interactive parts of it because it's supposed to be a spoof on video games and whatnot. But most of the first half of Homestuck is spent with John literally goofing off and not doing much, or the kids just kind of wasting time trying to get other things. I mean most of Rose's portion is her trying to find a place to plug in her laptop lol.
There's definitely a lot they can just cut and squeeze together so it fits with this new adaptation. And I think them showing Karkat so early is another reason for this, because obviously we don't get to see the trolls until way later, but this is a pilot and we have to show all of the most popular characters right off the bat to get people talking about it and interested.
I think if people really want a 1:1 adaptation then they're going to be really disappointed and should probably just reread the comic at that point lol.