Call of duty World at War had this in it, and I loved it.
I can asure you it's not the technology, because DOOM (the first FPS ever I believe) had mass amounts of gore and blood in it, and it came out in 1992. Compared to other modern games, DOOM is WAY outdated.
Wolfenstein 3-D, was one of the first (1992). Doom was 1993. But they both came from Id, so either way. [/Nerd]
I like blood and gore in my games, just as long as it isn't over done. Shotguns, RPGs, certain Sniper Rifles, and grenades are understandable. But pistols and SMGs should not be equal to M82s in the gore department (I'm looking at you Gears). Assault Rifles depend on what type of bullet.
I should know that cosidering me and my brother are using the bloody game engine to make our own Bionicle style of one. But yeah, give or take I guess. Thanks for correcting .
But yeah, gore is needed only when it needs to be there. If you're making a combat simulator, than yeah, dempending on the bullet and weapons people should get gibed because, well, it wouldn't be a simulator if they didn't.