Obituary is sloppy? no way you might not like their style or anything but by no means is sloppy guitar playing. What you call slow and dull i call density, besides if inflames is considered death metal that about tells you how wide the genre is. Your reference of "machine gun drumming" makes me think you are thinking about brutal death metal ( dying fetus, suffocation, skinless, disgore, gorgasm, etc ) wich is another thing but i think death metal has too many things around it today so the brutal death metal sub-sub-sub genre thing is necesary ( just like saying melodic death metal ).
This is why i dislike using genres i mean when you hear someone talk about gothenburg sound bands is like a sub-sub-sub-sub genre ( metal>death metal>melodic death metal> gotheburg sound )is really getting ridiculous.