Team analysis
Well as you really want a rate, I guess I will go ahead. As you might have noticed after battling a few times with it your team has quite a disturbing weakness to strong physical attacker and tbh not many Pokemon are capable of stopping it barring Hitmontop who isn't as useful as it is in UU.
Overall your weaknesses are well covered by all the Pokemon, however there is one Pokemon that finds a delight in taking on your team and that one Pokemon is Toxicroak who can start demolishing the important factors of your team when it is at 3x. However the Sword dance version isn't as threatening as the Bulk Up version who is with this also more frequent.
Type-wise you seem decently covered but you would have to rely on Pokemon that can easily be killed off so I do have to say that I will be remodeling your team but I will keep your mascot and Gyarados.
Team rate
First of all Ninjask is an unreliable Pokemon to use as you are not guaranteed to perform a successful Baton Pass and in the 5th Generation competitive battling as it can easily be stopped and seeing as you aren't carrying Toxic many Pokemon can set up on it and kill the switching-in Baton receiver. For this reason I recommend you replace it with a bug that has great utility in the 5th generation OU, Scizor. I suggest making Scizor your physical attacker over Gyarados as I will transform Gyarados into a more useful wall and Scizor is just more reliable for that raw instant power
Scizor @ Choice band
Trait: Technician
EVs: 192HP / 252 Atk / 64 SDef
Adamant Nature
- Pursuit
- Bullet Punch
- U-turn
- Superpower
A Choice band set is relatively one of the most excellent sets Scizor could ever wield. There isn't much to say just that Scizor is a much more reliable physical attacker then Gyarados and a way more useful bug then Ninjask.
Well Gengar looks fine to me. I was planning to replace it with Jirachi but now it brings you less weaknesses then Jirachi and as a scarfer it is much more reliable as it can outpace more with relative ease. And I also don't want to spoil this "darkness theme".
Ok, I decided that Gyarados is still very vital to your team as it helps quench the power of physical sweepers exceptionally well. Gyarados's sweeper set has been used so often on Showdown that it is so easy to counter and besides that you could appreciate some physical bulk and Gyarados makes on bulky Pokemon and with Intimidate, it can cripple sweeps easily and with this also serves as a very nice Toxicroak counter.
Gyarados @ Leftovers
Trait: Intimidate
EVs: 248 HP / 252 Def / 8 Spd
Impish Nature
- Thunder Wave
- Dragon Tail
- Substitute
- Waterfall
Although Hitmontop still has a decent utility in OU, it really just belongs in UU. It used to serve as a prime Tyranitar-lead counter but Hippodown is just used much more nowadays and with this Hitmontop has really lost it's utility even as a spinner. So for this reason I recommend that you replace it with Starmie as it is faster, hits harder, brings extra coverage when battling the weathers and has a much higher chance to successfully spin. I would say LO Starmie is what you would need as it hits things very hard on the special side, something you seem to be lacking barring Hydreigon's presence and Gengar's.
Starmie @ Life Orb
Trait: Natural Cure
EVs: 252 SpA / 4 Def / 252 Spe
Timid Nature
- Hydro Pump
- Ice Beam
- Thunder
- Rapid Spin
Like I promised and on behalf of your request, I decided to not move Hydreigon from the picture. Mixed sweeper Hydreigon is fabulous however I do think making it have a little more investment in special attack by changing it;s nature from Hasty to Rash would benefit you more. I have noticed that you have difficulties keeping Hydreigon alive due to so many Pokemon being faster then it now that it has no investment in speed, so I think the following set is what you need:
Hydreigon @ Life Orb
Trait: Levitate
EVs: 4 Atk / 252 SAtk / 252 Spd
Rash Nature
- Draco Meteor
- Superpower
- Fire Blast
- Earthquake
Yeah I believe that Earthquake would be more useful on this Hydreigon as right now most of your Pokemon aren't exactly capable of dealing with Heatran that well as they are threatened to be outpaced. Life Orb
4 Atk Life Orb Hydreigon Earthquake vs. 0 HP / 0 Def Heatran: 374-442
(115.78 - 136.84%) -- guaranteed OHKO
Yes as much a little countering my will I do believe that replacing Blissey with Celebi would be more optional. Despite being the Wall-o-Wall in Ubers, in Ubers danger lurks from behind every corner and I see it is your intention to make it a semi-physical wall but with the Gyarados she isn't really needed and she just brings unnecessary weaknesses. This is why I believe Celebi would be more optional as it's typing is bluffing and it forms a major threat to many weathers especially sand. It's perfect bulk cannot be overlooked so Celebi all the way.
Celebi @ Leftovers
Trait: Natural Cure
EVs: 252 HP / 4 Def / 252 SDef
Calm Nature
- Psychic
- Stealth Rock/U-turn
- Thunder Wave
- Recover
Well Stealth Rock or U-Turn whatever you think you need most for the rest this set is extremely annoying to deal with and leaves many opponents depressed when they realize that they can't kill Celebi with a STAB Shadow Ball >:)
Well this was all I have to share with you and I hope it has a form of utility for you. If you have any questions are anything you want to ask, please feel free and leave a comment,
Valet