I'd like to see the ability to customise your characters combat style, a la Jedi Knight 2, except much more detailed. eg you may want a flamboyant character, this could be shown in how you set up there combat style. They could spin the lightsaber in their hand before striking use unnessisary cartwheels, further this could have its benefits like enemies could be more wary of attacking this seemingly powerful character. Or drawbacks like becoming tired quicker or being more vunerable to group attacks. The possibilities to this in combat and having a unique character are to much to list.
Also item manipulation could interesting. Perhaps the ability to repair items which could be bought more cheaply. Construct unique weapons from buying parts and merging them. Construct items to make puzzles easier, eg find an item, to make it easier you could construct a metal detector. This shouldn't have to be constructed but left to the player to work out.
