audit1: You snagged the name “Combat Information Center” already, but I had the idea for a secondary bridge, used mainly when the ship went into battle. There would be specialized stations for Countermeasures, Threat Assessment and Internal Tactical (to coordinate against any boarding parties, leaving the main Tactical officer free to deal with outside threats).
Hull breaches are dealt with using emergency forcefields, which might sound wasteful of energy, but then using a transporter to transport large masses of metal to plug the holes seems more so.
Phasers can rapid fire, just rarely seem to. A good example is TNG: Conundrum, where the ship fires four rapid shots to take out some small fighter/drones. As for hand phasers, rapid fire to take out a large number of enemy targets is unnecessary; you can adjust it to wide-beam and just send them all night-night with one shot.
Security teams: sigh Yes, I too am sick of the endless “dead redshirt” syndrome. My security guys would either be able to shoot the wings off a fly at fifty meters, beat up Chuck Norris and Steven Seagel and spank 'em till they cried for mama, or be able to take a disrupter hit to the chest, say “ow” and then literally disarm the guy and beat him with the wet end. Starfleet BAMF: when you got to take out every MFing Romulan on the planet; accept no substitutes.
Holodecks: Far overused as a plot device, but still serve a real purpose. Hey, after weeks and months in space, crew efficiency would really slack off without some major release.
Rail gun: most of the armchair physicists here might disagree with me, but a phaser mount would probably take up less room, be easier to repair, able to change firing vectors quicker, etc.
Seatbelts: As I recall, the early TOS movies did have some chair support that snapped shut over the thighs in an emergency situation.
Armor: Yes, this would be a good idea, if not a full armored suit, then the sort seen in ST:TMP and (I believe) ST:STFS. Added head protection, a chest plate, and possibly a small forcefield generator allowing for short-term protection.
yojimboguy: As we saw in TNG: “Hollow Pursuits” there was (at that time) no Starfleet protocol that prevented one from making simulations of other people on board your ship. Troi, of course, was all for Barclay indulging his fantasy life – unless she came a cropper with the “Goddess of Empathy…” The look on her face, I could frame it and hang it on my wall.
The “EA-KH” is actually a cute idea, and semi-workable if you want to devote that much dedicated processing power to it. I really did like the holographic “false corridor” idea (“OK, down this junction he–” BONNNNKK!)