Well many of those search items would require some JOINS which are an expensive (high impact to the server) search. Many small sites could probably handle it but some of the bigger sites would just about lock up if all those search features were enabled.
There would need to be some other mechanism in place to allow only a couple advanced searches in a given period and alert the user to about it as well. Then it might be possible, otherwise without some type of control in place I think the big sites would be upset when there system crawled to a halt.
