While it may not be as powerful, having a better chance to burn while hitting with potentially super-effective or at least neutral damage can really help. As for GMaxing, raising your own stats is normally better than lowering you opponents, especially for a sweeper. In addition, the burn damage deals that extra damage that dragon pulse would, but a little less (more if it is super-effective).
Also, like Nebby said, swap Leftovers for Life Orb because you have roost.
Hope I helped!