Sorry it took so long, here's your rate.
You have several large weakness to common OU Pokes, while some of these can be fixed rather easily, others will cause you to rearrange your team structure. I'll start you off with your weaknesses, and then go to fixing them, as well as other minor bugs.
Rotom-W: Your team has no good way of handling it, and Chansey is the only one who can really wall it. However, most Rotom-Ws make use of Trick, which will render Chansey close to useless. Virizion could deal with this weakness, and could prove a practical revenge killer in place of Lucario. Virizion will still offer you a fighting type, and also offers a chance at a boosting mixed sweeper. The downside is that you will loose a priority move, although Dragonite's Extremespeed should be enough.
Choice Scarf Terrakion: OHKOes Dragonite, Chansey, Lucario, Gengar, and Volcarona. Replacing Lucario with Virizion will also help here as well, since Virizion can OHKO Terrakion and even take X-Scissors. Also if you see one, keep Forretress alive at all costs.
Rain + Tornadurs: Although Tornadurs isn't too common in OU today, he can still manage and OHKO on Volcarona, Virizion (If you take my set, and Lucario if you don't), Gengar, Dragonite (If rocks are up), Forretress (If spikes or rocks are up), and 2HKOes Chnasey. The best way to fix this, is by changing Chansey's nature to Calm so that she will have time to paralyze and pass a Wish before she is KOed. Gengar can also deal with Specs Tornadurs, but the Special Defense on Chansey will help a lot, and Timid doesn't offer much as it is.
Para Shuffler Dragonite: You have no way of dealing with it, and it can simply Dragon Tail away any of your stat boosting Pokes. Disable won't do much, other than disposing of a single move (Substitute blocks this anyway), and since Gengar is so frail, he won't last long anyway. The worst of it all is that this problem can't be fixed without making radical changes, and I'v already offered enough changes as it is. The good thing is that Para Shuffler Dragonite is very rare in today's meta-game, but keep an eye out for it.
Other Improvements: I personally like max Hp on Volcarona so that is has time to set up. Since Special Attack can always be boosted, and because you aren't using Volcarona for revenge killing, you probably don't need it on this set. Also Leftovers is a better item than Life Orb, since you have no other form of recovery without having to switch. Dragon Claw is also downright pitiful on Dragonite, and Outrage should be tested in its place.
Sets:
Virizion @ Leftovers
104 Atk/152 Sp. Atk/252 Spe
Hasty
-Work Up
-Close Combat
-Giga Drain
-Hidden Power (Ice)
Everything is yours to test, good luck Fate Itself
~Dragone