I have worked out the skeleton of the battle engine, and now I'm fleshing it out a bit. The basic way it works is, there are monsters on the battle field, and the player. The monsters + player are in a battle queue; each time their queue time says they should be next, that queue time is subtracted from everything else (so the queue moves ahead) and they are given a turn, during which they will presumably set their queue time to be next)
What is cool about this, is that attacks can be split into multiple turns. So when a dragon does a jumping attack, it might spend .3 seconds preparing to jump, and 2.8 seconds in the air.
If you are attacking with a sword, and your attack happens sometime during the "preparation" turn, you will hit it since it's on the ground, and, possibly, keep it from doing it's next attack. If OTOH it's in the air, you will get a message like, "you swing at the dragon which is flying over your head, and miss"
So there is a real possibility for interesting interactions, hopefully I can leverage some orthogonality (at least, monsters having a flying flag or something such as that) to get some unexpected consequences.
In the previous example, say you shoot at a dragon while it's flying. Since it's a ranged weapon, and the dragon may have it's belly unusally exposed, you may do extra damage. Moreover, you might be able to rattle off a few shots while it's flying. I can of course have something like, a movement parameter that says how fast the target monster is moving.
The point of all this ISN'T in order for you to hold it in your head and work out on paper the likelihood to hit in each situation. Rather, the purpose is to create a genuinely intuitive battle system, with interesting, sometimes unexpected and above all really varied battle situations.
I have thought for a long time about implementing something like this in a graphical sense, except then it really just becomes realtime battles. Turn based battles really aren't like this in any games I've played, at least (usually, turns are instantaneous, which is somewhat true here, it's just that turns may be multi-part and be interrupted, etc.)
So HA! Soon monsters should be battle-able and so on and so forth, it will be quite an unusual dichotomy you know, half the game as full 3D expansive space exploration, and half of it in text adventures. Bizarre, but this is after all an evolved not constructed design so we expect some unexpected shapes to present themselves.