I suppose the answer is look to other genres. Recent RTS games allow for a context sensitive cursor that spirals out to offer more than one choice whilst keeping the screen uncluttered, and it's not something I recall seeing in any recent adventures. In BF2 hitting Q or T on the keyboard brings up an easy mouse-manipulated menu system to issue commands or responses.
The idea would be to keep the three-button system and scroll wheel, but using an easy, maybe icon-driven, menu interface you'll have more options than just a simple one-option click.
Left mouse would be look at, middle mouse touch, right mouse menu with the scroll wheel clicking up and down the options much like an i-pod. Inventory manipulable objects would show your inventory in the menu when clicked on, items without manipulation would offer fewer menu options.
In 3D maybe even a lock on, if converting to a console system, much like Metroid Prime offers with usable objects or backgrounds only requiring entering into a medium fov before being able to use the lock as not to confuse the player between close hotspots. Maybe when not in menu mode on PC, the scroll wheel would cycle avatar attention between different objects.
This doesn't overcomplicate, and after a brief introductory train it'd be quite simple. No reactions are needed.
Here's the only shot I could find of the BFME menu system -
As you can see, I'm talking more about the context-sensitive cursor spiral at the top rather than the menu at the bottom.
