I thought the same thing when I first smelled this new food, to me it didn't smell that great however steve cannot wait to get his teeth into it! The last food I was giving him he would quite often turn his nose up at and leave for a few hours before eating - especially if he was tired.
Rottweilers are rarely picky about their food mind - if they are hungry, they eat lol.
One note though, if you do change his food be sure to do it gradually over the course of at least a week, preferably two or more to give his digestive system a chance to adapt. Suddenly changing a dogs diet (especially a rottweiler as they have the shortest digestive tract compared to their body size of any breed of dog) can cause major discomfort for the dog in the form of diarrhoea or constipation. A lot does depend on the dog themselves mind. Chad has a cast iron gut - I think he had problems perhaps once a year. Steve on the other hand is more delicate although that may be due to the massive infestation of worms he had when I first got him that took over six months to fully cure damaging his intestines a little. (Poor puppy
)