Department of Homeland Security did not unite our intelligence agencies. CIA, DIA (Defense), and others were not included. They all work in the same arena and need to be separate IMHO from the rest of the Homeland Security in order to stay independent. FBI stayed separate as well from Homeland Security.
Putting all the Intelligence under the head of Homeland Security would be too much for anyone person to handle. The head of Intelligence needs to deal directly to the National Security Advisor IMO along with the Director of Homeland Security. Putting them under Homeland Security could possibly cause a delay in the President receiving vital information.
Rose Garden announcement of this at 11:20 today.