That is a terrific idea. The regular dialogue options should be there, but enterprising players should find unusual or stange dialogue options if bothering to try them. This search window is an excellent idea. Something like that has been implemented in Fallout, but noone ever used it, as nothing came out of it. I would very much like an encounter, where rational thinking and an in-depth knowledge of the game would bring you some rewards. Like in PS:T, where a conversation with Dak'kon would result in new spells, and bonuses to the ally.
Choices
I would very much like multi-lateral