Scientists love to have the power to control nature, but often without the understanding of the effects of controlling nature. There is no way that controlling hurricanes so that they are redirected to less populated areas will fail to have unintended consequences. If hurricane Katrina could have been diverted from New Orleans, where would it be diverted to? The entire area is relatively heavily populated.
Once hurricanes hit land, the land mass acts as a "brake", slowing the forces of the hurricane. As a storm works over warmer surface ocean temperatures in a shallow ocean that has enough space for the forces to build up. The method of cooling of millions of square miles of ocean surface would possibly stunt the growth of the storm. Heating the atmosphere? Who knows what that would do? There is no technology for cooling the atmosphere on a scale that could affect a huge storm.
It would take far more than Dr. Evil's "One Milllliiioon Dollars!" to fund such an endeavor. The fact is that, once scientists get the capital investment for the massive operation, they would definitely be under government control. Government control means political control and the liklelihood is that strategic or corporate interests would come first, not people. There would be a maze of competing political demands that would affect decisions to determine how and when the approval would come for any kind of storm diversion or modification of the environment to redirect a storm.
The scenario of a James Bond-esque "bad guy" who is bent on world domination by threat of hurricane diversion is an unlikely one, when we go back to the massive capitalization that would be required in order to fund the technology of hurricane diversion and control. Only governments could call for, or divert, such impossible levels of funding, making the likelihood of developing the technology more on the lines of a weapon, than as a force for controlling nature for the good of humanity.
As a result, there should be no waste of funds on programs to control or to divert hurricanes. It would be more successful to direct money and attention to the quality of human structures, and the location of highly populated cities, so that they can withstand or be located away from the worst that nature can bring.
And we know that structures can be built to withstand the forces of hurricanes, to reduce the death toll from earthquakes and to stand up to tornadoes, yet humans insist on living on the sides of active volcanoes, building substandard homes in the path of storms, getting around earthquake code enforcement, and settling in places that will, from time to time, suffer from the wrath of nature.