Better post before I forget. Can't think of anything else to add at the moment. I'll edit if I think of something. Thank you.
[SET]
name: Life Orb
move 1: Thunderbolt
move 2: Shadow Ball
move 3: Hydro Pump
move 4: Pain Split
item: Life Orb
nature: Timid
evs: 4 HP / 252 SpA / 252 Spe
[SET COMMENTS]
<p>With dual STAB accompanied by Hydro Pump, Rotom-W can become a big threat to unprepared teams. Its STAB moves leave little to be desired, only resisted by Magnezone and Steelix in standard play. Hydro Pump allows Rotom-W to hit both of these Pokémon, and more importantly, OHKO Heatran and 2HKO incoming Tyranitar. Although the final moveslot can be changed as you see fit, Pain Split is recommended as it is a great move against Blissey. With max Speed, Rotom-W is faster than Adamant Lucario, which allows you to revenge kill him. Some other notable Pokémon Rotom-W outspeeds are Naive Heatran, Timid Suicune, and Jolly Gyarados. Gliscor and Swampert work well with this Rotom-W, as they easily counter Choice Scarf Tyranitar, who is a huge threat to this set. Heatran is a great Blissey lure, and can kill her with Explosion, allowing Rotom-W to sweep unhindered.</p>
[Additional Comments]
<p>There are many other moves Rotom-W can use in place of Pain Split : Toxic takes care of most walls, including Blissey. Charge Beam can grant Rotom-W a Special Attack boost on the switch, and Will-O-Wisp will burn Tyranitar, reducing damage against your team. Substitute is a good move to scout the foe's switch-in, and avoid any Choice Scarf Tyranitar coming in. The ability to evade status is also a great help, especially against Blissey, who otherwise cannot harm Rotom-W.</p>
<p>If you plan to sweep with this Rotom-W, you'll need to weaken the foe's team and eliminate threats such as Tyranitar, Blissey, and Snorlax. Heatran does heavy damage to incoming Tyranitar and can also blow up on Blissey. You can also attempt to Trick Blissey with a Pokémon such as Starmie. A Blissey locked into a single move is easily beaten by Pain Split or set up on with Charge Beam. Scizor and Breloom are both excellent counters to Blissey and good checks to Tyranitar as well. If you plan on using Rotom-W as a Heatran or Tyranitar lure, try using Hydro Pump as often as you can, as Choice Scarf Tyranitar will outspeed and KO Rotom-W with Crunch. This can help set up a sweep for Pokémon such as Nasty Plot Azelf, Life Orb Starmie, and others who dread Choice Scarf Tyranitar. If you lure and kill Heatran, Scizor can also set up and sweep more easily with Swords Dance. Machamp is a great counter to Tyranitar, and can set up a Substitute or Bulk Up on those locked into a resisted attack.</p>