Funny, this reminds me SO much of the stuff I recorded when I first started years ago -- which is a good thing. I'll have to dig out my Pantera CDs and reminisce.
The drum issue: I'm not quite as down on the drum sound as some. You have some really nice hi-hat work in there and nice drum work in general. And for what you have to work with, you've done really well. Still, I would agree that different samples would be an improvement.
The bass issue: The bass does need to come up in the mix. I don't think it's volume that's making it "boomy," I think it's the actual bass sound. I'm not sure if you're putting that "boom" bass drum throughout the song or if you just have a really fat, echo-y bass guitar sound, but there's definitely something "boomy" in there. That's probably not much help, but I think a tighter overall bass sound with more volume and punch would add to the song -- as opposed to the ethereal, in-the-background bass sound you have going on right now. This is a gut-puncher, in the vein of Pantera, of course, given your handle, and the bass should reflect that. Just a thought.
Anyway, I'll also echo the sentiment that it's nice to have a metal poster here. Don't get to hear much of that. I cut my teeth on this shit, and because it's somewhat out of style at the moment, I don't hear a lot of new stuff. Thanks for posting!
By the way, if you've never listened to Meshuggah, that might be up your alley. They have the best drummer to ever live (IMO) -- with Tool's drummer a close second -- EXTREMELY complex arrangements (bordering on "math rock"), and a VERY HEAVY sound. New Millennium Cyanide Christ will have you at your guitar instantly, trying to figure out the insanely complex guitar riff timing.

I really think they're the best at this kind of music. Just a friendly suggestion!
Piltdown Man