The only thing I would possible suggest on the team is perhaps a Scarf Gengar instead of Azelf.
Gengar @ Choice Scarf
252 Atk / 252 Spe / 6 HP
- Hidden Power [GROUND]
- Shadow Ball / Trick
The reason I suggest Scarf Gengar is so your team has a way to stop Dragon Dance Gyarados (besides clever intimidate switching)
With this you can possibly revenge kill Heatrans who are not expecting Hidden Power (GROUND) and Trick a scarf to an unwanted pokemon. Then to put the icing on the cake you'll be able to explode (not as powerful as Azelf) taking a Blissey or a strong wall down with you.