THIS IS NOT EGOISTIC.
The amount of people who have asked me to explain my team is pissing me off, so I'm going to do it here, as it could provide a good learning experience for everyone.
My team runs a base of fast paced and aggressive sweeping natures. It has two sweepers, being Tyranitar and Jirachi, and revenge killers being Zapdos, Heatran and Jirachi could be used again. Then I have Kingdra, which can smash down walls and then I use Forretress to take any sleep directed at me, same for most attacks.
Dragon Dancing is a significant threat, and I count it with two things.
Zapdos has Thunderbolt which hits Gyarados for an OHKO, even with Wacen Berry equipped.
It also has HP Ice, which OHKO's Salamance and Alteria and depending on the Dragonite 2OHKO's it. It can outspeed ANY Salamance, Dragonite, Alteria or Gyarados after a DD.
Scizor is the most dangerous threat in the metagame as of Plat changes, and I counter it with Zapdos or Heatran.
Ok, so Jirachi is steel and Psychic right? Its instantly weak to fire and ground from its steel part, but not weak to dark because of steel, and fighting hits it for neutral because of steel. So you want to have a move which can hit ground and fire Pokemon on Jirachi, or stay away from them.
For ground, my Jirachi has Iron Head, which hits them for super effective, and gets a same attack bonus. Jirachi can not counter Fire, so its best to switch out of fire. I use it as a lead because of Serene Grace, which increases the flinch chance of Iron Head and Zen Headbutt, and I give it a choice scarf to hold so it can become really fast. If I can damage it, I use Iron Head or Zen Headbutt, or I could set up Stealth Rock, hitting all switch in Pokemon, and I could U-Turn, damaging it and giving me a free switch.
My choice scarf may limit me to one move only, but the only thing I need to worry about are Magnazone and Heatran.
It reaches a speed of 430+ with the scarf equipped, so it out speeds most threats including Dugtrio when it holds a choice band, but not including Scarfed Heatran.
Dragon Dancing is becoming dangerous, with the metagame becoming more stall based it is much easier to find time to set up one or two dragon dances, so I needed a fast, powerful Pokemon to deal with these threats, and I found Zapdos.
Zapdos is normally used Bulky, so by changing its EV's to a revenge killer set, and then scarfing it, Zapdos is now able to outspeed Gyardos, Alteria, Charizard, Tyranitar and Salamance if its not running Jolly. I gave it Hidden Power Ice to OHKO Alteria, Dragonite and Salamance, and Thunderbolt to OHKO Gyardos even through Wacen Berry. Charizard is taken out easily with Thunderbolt or Hidden Power Ice.
I then started to see Steel's, namly Scizor switching into this set, so since Zapdos got Heat Wave, I put that in moveslot three, and then to help with double switchers, I gave it U-Turn.
Zapdos can scout in tandem with Jirachi to reveal the opponents team.
Latias has a speed of 350, allowing it to tie with many powerful Pokemon, and also is fastest of all the dragons in the OU metagame, so using it was a must. It bears one of the most powerful Draco Meteors around in the game, doing 45% to Bissey. So I looked at Latias, and decided that since its fast, a specs set would become highly useful. With its attack being around 400+, and with STAB on Draco Meteor, it has become a highly lethal threat. Seeing as my team is weak to Swampert, I chose to tack Energy Ball onto it, allowing the easy OHKO on Swampert. It has Surf to make up for what Draco Meteor cannot hit, Steel Types. I used to run Psychic in the last slot, but after seeing that everything I would hit with Psychic takes immense damage from my other moves, I decided to run Thunderbolt, but changed it again for Dragon Pulse. Dragon Pulse gets STAB, 1.5x boost from Choice Specs, and it only slightly weaker than Draco Meteor, making it perfect for sniping off weakened teams.
I used to run a Kingdra here, but when I saw Latias was faster and better than Kingdra, I switched.
It is Ice weak, but Heatran takes care of any ice moves directed at it.
As mentioned previously, Dragon Dancing is becoming lethal. Gyrados is expected, Salamance isnt dealing with SR well, and Dragonite is inferior to Salamance, and Alteria is lol.
So I looked at Tyranitar, and it became a beast. Even with nothing in Attack, it is still a stat not to be laughed at, and then I can invest the others into bulk, allowing it to live.
With Sand Stream, it gets an advantage in the way its SpDef is boosted, and considering that 3 of my team are immune to Sandstorm, I couldnt see what the issue with it was, allowing Leftovers to be cancelled out on all annoying walls.
It gets STAB from Crunch, so that went on the set along with Earthquake, and then my last choice was Outrage. Outrage is only resisted by Steel Pokemon, making a high powered sweep easy to achieve.
So with Jirachi serving as my annoying lead, I normally don't have time to get entry hazards up. Entry hazards such as stealth rock can do up to 394% or as little as 36% to the opposing team, so it is a vital move on any group. Since I have to need for status, I also chose Toxic Spikes, and the best way to set both of these up is with Forretress.
Its also rather bulky, so I use it as my rapid spinner, so no entry hazards can annoy me, and lastly, I used Gyro Ball on it, using Same Type Attack Boost and its low speed, it reaches a power of up to 300 damage.
I gave it a careful nature so it can take the most damage from Special Attacks, being as it is naturally bulky.
However, like Jirachi, it has a fire weakness to it, making Scarfed Heatran appear troublesome.
Type coverage is often best, there are loads of types and you need to have some way to deal with them all, should they switch out on you.
Dragons are the most deadly, for they are only resisted by rock and steel, so you might want multiple checks for a dragon, such as someone with an ice move and someone with a dragon move.
Considering the number one threat is still Scizor, you need something that can deal with Scizor, and another threat is Tyranitar. I went for a Fire Pokemon to hit Scizor, and then I chose Heatran to hit Ttyranitar with Earth Power for super effective, then I went with Dragon Pulse so it could hit dragons, and to ensure it could hit many Pokemon quickly, I gave it a choice scarf so it could outspeed threats and ensure they wont want to stay in against Heatran OR to make sure Heatran can cripple them so they can be killed easily and quickly.
Quagsire can kill all your pokemon. EQ your jirachi/T-Tar/heatran. immune/resists most of zapdos's attacks and can hit back with stone edge and also resists kingdra. Only forrestress stand up to it really but then il ljust put a fire pokemon in and kill it :D lol. NB. i dont have any fires.
Ah, but where would you switch Quagsire in?
The only safe opening is when I T-bolt something with Zapdos, meaning I could switch to Jirachi, and then Iron Head it to death, and if Ttar gets a DD its an OHKO ON Quagisre.
Actually i doubt a DD T-Tar could. Mine has survived 2 DD gyarados' and Salamence. I could switch in on anything when one of my pokemon dies. And as you said gliscor, why not get rid of dragon pulse on heatran and give it HP ice. Does same job as dargon pulse to dragons if not better.