I agree with Everstone - I think the weakest link to this team is Gardevoir and Murkrow; you're effectively cutting your offense in half by having these mons that does not attack. It is somewhat contradictory the offensive nature of your other mons.
I also support
Tornadus > Murkrow. Partner Tornadus with Infernape, and you can stop Trick Room teams (Infernape Fake Out the non-Trick Roomer while Tornadus Taunts the Trick Roomer). Tornadus also possesses Tailwind to boost Rampardos's Speed. Even more Tornadus is a faster mon that can OHKO Latios (with Flying Gem) before it can retaliate. It actually pairs well with Rampardos, since it is immune to EQ and removes Fighting-types with Acrobatics. You could possibly remove Zen Headbutt for other options, like Head Smash to bypass Wide Guard and have a move to inflict 61% min on specially defensive Cresselia.
Unlike Murkrow, Gardevoir has some useful Special Offense, so I would use it. I would give it
Psychic over Imprison. I would also consider experimenting with other interesting support options over Thunder Wave, such as
Ally Switch, Helping Hand, or even Heal Pulse, all of which may allow it to function better with other partners.
That Gardevoir is a rather awkward mon, though. You can always pair Kingdra with
Gastrodon, which would rack up Special boost from opponent's and Kingdra's Water moves and can retaliate with its fueled special offense. Alternatively, you can replace Kingdra's Surf for
Muddy Water which hits both enemies and leave Kingdra's ally unscathed. The 85% accuracy is slightly off-putting, though.