I worded it badly, my main point was that either way we get much of the same resault, but alas, the discussion itself is more important, and I apologize for that remark, but right now lets look at some mew sets that can be effective!
I'll be using the original version of the theorymon and will put *s around where the multitype version comments go
Set: NP Water Sweeper
Mew @ Life Orb *Splash Plate*
Type: Water
Trait: Type Change *Synchronize*
EVs: 252 SAtk / 4 SDef / 252 Spd
Timid Nature
- Surf *Judgement*
- Nasty Plot
- Thunder
- Roost / Ice Beam / Baton Pass
This set lets mew be insane under the rain, with 1 boost and great resistances and a favoring weather to work with, this lets Mew really destroy lives, with NP, Life orb *Splash Plate* and a rain boosted STAB surf *judgement* it will 2HKO and OHKO some crazy stuff that you thought could switch into stuff like keldeo and starmie.
for instance, ferrothorn is demolished by this set, celebi is smashed by surf as well, and ice beam guerentees the OHKO vs 70 HP latias and 2HKO after CM on CM latias, while surf can 2HKO offensive anyway, also
this is the only *good* water type in OU with nasty plot and thunder letting it get past stuff like jellicent and other bulky waters with pure ease, also it's probably one of the most well rounded offensive waters, with 100 across bulk, 100 SpA, and 100 speed tier.
Here are some calcs to show the power of mew after an NP:
Standard Sets:
Special Wall Jellicent
+2 252 SpA Life Orb Mew Thunder vs. 252 HP / 220+ SpD Jellicent: 406-478 (100.49 - 118.31%) -- guaranteed OHKO
Standard Ferrothorn
+2 252 SpA Life Orb Mew Surf vs. 252 HP / 208 SpD Ferrothorn in rain: 187-220 (53.12 - 62.5%) -- guaranteed 2HKO
Specially Defensive Celebi
+2 252 SpA Life Orb Mew Surf vs. 252 HP / 236+ SpD Celebi in rain: 183-217 (45.29 - 53.71%) -- 1.95% chance to 2HKO
+2 252 SpA Life Orb Mew Ice Beam vs. 252 HP / 236+ SpD Celebi: 328-387 (81.18 - 95.79%) -- guaranteed 2HKO
Offensive Latias (70 HP spread)
+2 252 SpA Life Orb Mew Surf vs. 74 HP / 0 SpD Latias in rain: 201-238 (63 - 74.6%) -- guaranteed 2HKO
+2 252 SpA Life Orb Mew Ice Beam vs. 74 HP / 0 SpD Latias: 359-424 (112.53 - 132.91%) -- guaranteed OHKO
Calm Mind Latias
+2 252 SpA Life Orb Mew Surf vs. 252 HP / 0 SpD Latias in rain: 201-238 (55.21 - 65.38%) -- guaranteed 2HKO
+2 252 SpA Life Orb Mew Ice Beam vs. 252 HP / 0 SpD Latias: 359-424 (98.62 - 116.48%) -- 93.75% chance to OHKO
Specially Defensive Jirachi
+2 252 SpA Life Orb Mew Surf vs. 252 HP / 236+ SpD Jirachi in rain: 368-434 (91.08 - 107.42%) -- 43.75% chance to OHKO
Wall Amoongus
+2 252 SpA Life Orb Mew Surf vs. 252 HP / 228+ SpD Amoonguss in rain: 214-252 (49.53 - 58.33%) -- 64.45% chance to 2HKO
+2 252 SpA Life Orb Mew Ice Beam vs. 252 HP / 228+ SpD Amoonguss: 382-450 (88.42 - 104.16%) -- 31.25% chance to OHKO
I'll edit this post with more sets when I come around to writing them