I remember once reading a quote or something from Matt Jeffries, the original designer of the Enterprise.
When placing the high-power warp nacelles that powered the enterprise, he put them on struts so they'd be far away from the crew habitation spaces. In case anything went wrong with these (comparatively) massive engines, the crew won't be in danger.
This is a fine example of how far TNG has gotten away from the original vision of starships in the golden age of trek.