It would be amazing to have a Boolean option in the extrusion, for negative operations...
Negative extrusions in max are really anti-intuitive and we need a lot of work to use them in hard situation.
With an optional "boolean" option negative extrusion could be really smart and sketchup like
Here is an example of an obvious situation where it would be greatly usefull... Just create a 3x3 Cube and do a negative extrusion on a side quad.