One piece of the excess is the myriad of huge staffs working on amazingly insignificant projects in the government. We do not need separate staffs in every agency of every department coming up with EEO training, etc. All that common training could come from OPM.
Some of the general computer based training - NOFEAR Act, etc., does span agencies now. But there is room for expansion of that. Law enforcement is another area with a lot of overlap. Does every agency need its own armed police force?
I agree that there is room to slim things down for the benefit of the taxpayers, but the analysis needs to be done by folks with integrity.