Oh yeah on Kingdra i had a similar idea using it mixed.
Try this
Kingdra@Life Orb
Lonely Nature
54 Hp / 196 Att / 244 sp.Att / 16 speed
Ability: Swift Swim
- Waterfall
- Draco Meteor / Dragon Pulse
- Surf / Hydro Pump
- Rain Dance
All it needs are 16 EV s in speed to become the fastest Non-Uber in rain. Also in Rain it 2hkos Blissey with Waterfall. Ice Beam is kinda redundant due to the only thing fully walling this is steel and you hit those with Water moves any way (The Life Orb'd Dragon moves will beat other Dragons regardless). Dragon Pulse if you want it to stay in the battle longer. Draco meteor for get in, sweep, get out.