It would be nice if the server had a parser which converted polite expressions into base meanings.
For instance "Please can i have" could be equated with "give me". With a number of such conversions there would be one lookup table that passes the appropriate flag to indicate a correct trigger response.
Having said that, if you are going to go with the tree menu dialog this is moot. If the current system is to be kept it would simplify things because scripts would not have to individually trap for specific sequences of words and interaction with the npcs would allow for more player characterization.