A lot of people seem to no longer be interested in gore but I feel if it was brought back in a big way it would sell very well. Take that game active shooter. It was implemented poorly but the actual idea has major game play opportunities. Here are the features that would make my dream game set in an active shooter like game.
>Each level would be a fully rendered building that could be completely destroyed
>Each character in the level would be fully rendered inside and out including organs
>You could dismember, disembowel, shoot or cut out any organ you want
>Characters react to being shot
>You could partially dismember
>Characters would have shock effects, panic effects etc
>Depending on the weapon used and the environment NPC's could hear sounds that could cause panic
>Stomachs would have liquid contents that could be spilled
>You could select the race, gender, height, weight and general looks of all NPCs in a sandbox mode
>You earn experience points which unlock items that are themselves gameplay mechanics such as a chain to close doors to corral crowds in hallways or bombs to open doors or collapse parts of buildings etc
>certain levels would be high score soft targets while others would be missions where you would have to deal with the law