It should be ok as you propose it, Argh. I think it has alot of promise for creating a vast, interactive world. I know that's your vision for TMW, and it's mine too.
That system gets really explicit though, since we have to define a list of cases for each entity. I'd like you to come up with a complete list of the possible cases that outline every possible action an entity can perform on another. (15 or less would be a good number to shoot for). This would make it easier on programmers.
Also, try to be as generic as possible.
- Drink and Eat can be combined.
- Push and Pull can be combined (with a negative value passed to push)
- Store and drop are the same (you're just storing the object in the world)
- Bite -> Attack (all actors can attack, we only need one function for it)
- Fire Up, and similar actions can become -> Activate
- Fire Down, and similar actions can become -> Deactivate
You need to come up with more classes. Now you have Actors, but we'll also need:
- Stationary Objects - Items that can be used, but not stored. (barrels, oven, etc.)
- Tools - Items that can only be used or stored, and have no storage themselves (potions, rope, meal).
Also, I have to say I'm against using push and pull too much. Players may be able to rearrange objects in their own homes via the Player Estate System, but they shouldn't be able to move other people's stuff around, especially the scenery in towns. Maybe if he has special permission or such... but that ties more into the political system...
I would actually suggest excluding items that fall into "tools" from the system altogether. Only use this object system for items that don't go into the player's inventory, the ones that he interacts with on the world map. It's pointless to have 15 acting functions for an item that can only be used or stored.
This system also provides a valid basis for the NPCs to be derived from, since they are just objects with talk scripts attached.