Not only is it small units, but top-heavy ones, too. In "Siege of AR-558", there are 150 troops on the planetoid originally, commanded by a Captain, a Commander and a Lieutenant - that is, a Colonel, a LtCol and a Captain, respectively, but naval names are used. That's plenty of brass for just 150 men and women!
It might well be that the future definition of a brigade or a regiment, worthy commands for a Colonel and currently multi-thousand-man formations, is just 150 men. If armed with phaser rifles, the 150 should certainly produce as much firepower as a regiment or perhaps even a brigade today!
Alternately, perhaps a ground troop is more like "naval infantry", a bunch of starship crew members pressed to surface fighting duty. The 150 would be the security complement of the ship normally, but now they become infantry, and their leader, a Lieutenant or a Lieutenant Commander as in TOS, becomes subordinate to the captain of the ship that deployed the men and was then sent elsewhere under the command of a junior officer? The need to place troops on AR-558 was a strategic surprise to Starfleet, after all, and the desire of the skipper him- or herself to stay with the troops may have emerged only when they found out there was this hugely important communications relay down there.
Timo Saloniemi
