You may want to take a look at dragonrealms, http://www.play.net/dr/ (You can of course take this reply as one from a gamer, and not one skilled in creating a game)

It is a text based game with combat, it has been years and years since I played it, but you would enter into stances and ranges, and make various attack types as your opponent would be in other stances. Anything from laying on the ground dead, to kneeling, standing, tiredness. A lot of the actions were based more on a players skill value and what you were doing and not so much die rolls. I think, its been a while. It would take pages to detail all of the commands, here is a link to many of them if not all of them. http://www.play.net/dr/info/commands_all.asp

Many commands are emotes and other non combat commands, way more commands than you could have buttons on the screen for. But you could have some form of radial wheel or drop down menu that could be navigated to select a command with point and click. The nature of many commands is such that you may have an action, and a target thing you are interacting with, and maybe some modifier word that helps define how you are interacting with that thing. Instead of punch, or punch the monster, it may be punch the monster in the head.

For a real text based game you may as someone above said need to look around, and be able to freely see every bit of your surroundings before you even make an action like a movement. And then that would have to be figured into the combat timer. Monsters will periodically advance to the next round, giving you maybe 30-45 seconds to type out your action for your round. Unless you go about having time stop at every instant and let the player consider in depth every possible action before proceeding.