
I love Receiver, so I couldn't really care less about the "Doom-feel" if you can manage a "Receiver-feel" in Doom. (And then my mind goes wild with thoughts of detailed weapon modification systems and controls for breaking your weapons down, etc... sorry, I'm not expecting that level of ridiculous from you, just some minor ridiculousness will do).
Anyway, that's my two cents. I can relate to your feelings about sprite work; it makes a project take twice as long or longer to run a one-man band like that. Maybe an artist in the community will offer a helping hand somewhere down the road?
EDIT:I'm imagining some kind of crazy 2.5D HUD weapon made of all these overlays - like if the nice 3D-looking effect of your crosshair could be applied to an entire weapon. THAT WOULD BE SO AWESOME. I'm not really expecting that, of course, but still...