I personally think that too many people have grudges against deathcore and grindcore to appriciate at least a couple good songs. These bands are just like Britney Spears in the sense that the labels have to tell them to make hit singles, and the rest of the songs are boring crap. BUT that is how all american music is. It has nothing to do with the genre. Deathcore would be an amazing genre, a genre I'd listen to all day long, a genre I'd love. But sadly, it will probably never be, just because most of the kids just want brutal shows, and no deathcore bands are willing to make catchy, epic songs like BDM's Statutory Ape, Suicide Silence's Lifted, Cattle Decapitation's Humanre and Gardeners of Eden, even these bands themselves don't make anything good if its not a single...its even the case with other metal bands like Dimmu Borgir. Dimmu pretty much isn't very exciting but the song Progenies is just epic.
It truly is mostly an american band problem, all these bands just know they can make good hits and not worry about the shit thats on the rest of the cd. the rest of the cd all will sound the same, but way more boring and less experimental. And opposite of that, you could take really talented always different bands like Dark T, Opeth, Cradle of Filth and even In Flames, and what makes them talented is EVERY SONG IS DIFFERENT. Different tempos, different parts, different choruses, different lengths, and different influences and sounds. Bands that always sound the same are boring, and deathcore would be amazing if the bands didn't always pride on each song being an exact clone of another.
I mean, wether anyone realizes it or not, DT's The Gallery was essentially the first album to dab in what would be now called Deathcore. It just had the begginings of what would evolve. But they proved that you can have a brutal, evil, epic album that is insanely catchy and melodic, without really being all that experimental. it just takes talent for writing riffs, vocal lines, and different parts with different influences across the metal span.