...
At least this could explain, why the phaser control room has the same height as the engine room: Behind the separating wall there are racks with all the various and mission specific probes.
Bob
I've thought this for years. It's actually taking up quite a bit of space on the saucer. It's kind of a pain in the butt, but I'm working with it for now...
I've been able to fit three of those rooms into the primary hull roughly between where the phasers are on the dorsal and ventral of the saucer. The two giant vertical columns in the room could be the power feeds to the upper and lower phasers for each room. Alternatively, the forward room might be extra large because adjacent to it is the automated photon torpedo launchers in the ventral part of the ship...
But yeah, they do take up a lot of space.