Alright, I decided to do something weird and use Reversal Victini.

Nike the Victini @ Salac Berry
Ability- Victory Star
Jolly/Adamant Nature. 252 Atk, 252 spd, 4 def
V-Create
Bolt Strike
Reversal
Endure/Substitute
I think this set would function as a good late-game sweeper. At 1 HP, Reversal hits a whopping 200 base power. This allows Victini to hit Tyrannitar and Heatran for major damage (more importantly Heatran). Substitute or Endure would provide Victini buffs to get it to the range where Reversal hits 200BP. V-Create and Bolt Strike are pratically mandatory for Victini, V-Create is the move that smashes pratically everything, while Bolt Strike nails water types like Politoed and Jellicent.
There are disadvantages to this set, though. Pursuit users like Tyrannitar can nail it if it tries to switch out. Lucky for Victini, users of Pursuit and Sucker Punch (Houndoom and Bisharp), aren't that common in OU, and Tyrannitar is easily smashed by Reversal. However, you still need to be wary, so a Fighting type would be nice to have (specifically Mach Punch users like Breloom, Conkeldurr, and Infernape. Infernape and Conkeldurr have no trouble with Houndoom or Bisharp, while Breloom has to be wary of Fire Blast from Houndoom). One also needs to be careful of priority users like Lucario, so having priority on you own side helps too. This set is good for having great speed (through Salac Berry) and the ability to switch moves at the cost of losing to priority and residual damage.
Ninetales is a great teammate, removing sand and hail damage and boosting the power of V-Create with Drought. Infernape can also abuse the sun as well as take down Tyrannitar and Abomasnow, which are this Victini's worst enemies. Cresselia, infamous for being a sun tank, can use Ice Beam to take down Salamence and Dragonite, both which can take a hit from V-Create and retaliate back. It also has Lunar Dance to recover the health of a badly weakened teammate. Hippowdon is a problem, being able to take hits from the entire team. Xatu would then be a fine team member, bouncing away hazards and counting down Hippowdon's turns to live with Toxic. Finally, despite already having Xatu, a rapid spinner is almost always needed in a team, especially here, where Victini can die out to hazards. Forretress or Starmie are good candidates. The former being a steel type and the latter taking out Terrakion. Cloyster can also be considered, being a deadly Shell Smash sweeper. As Healing Wish heals before hazards, one can consider an alternate steel type if hazards aren't a concern.
If you're wondering, Politoed isn't a huge problem. As Victini can switch moves, it can just Bolt Strike Politoed whenever it wants to. Sunny Day Ninetales also ruins the frog's day. Still, it's something to watch out for.
Crap, I went too far, didn't I?