Moltres's advantages over Volcarona are way better physical bulk, to the point that he can actually be a pivot for physical Fighting/Bug/Steel attacks while using an offensive ev spread, 50% more power when using Hurricane (due to STAB), and the ability to pp stall things it can't beat with Pressure.
This and Agility...
If i were to use a set i would use the offensive Modest LO one with Hurricane, Fire Blast, Sub, Roost and LO in rain. Standard Hurricane resists and SpD walls are all 2hkoed after SR or PP stalled out of their dangerous moves with SubRoost except from the blobs. Standard Lefties Rotom-W is always 2hkoed by Hurricane after SR, SpD Jirachi is 2hkoed by Fire Blast, SpD Skarmory is easily 2hkoed by Hurricane + Fire Blast and Physically Defensive is OHKOed by Fire Blast, Jolteon and Thundurus-T are 2hkoed by any move w/o SR, Metagross is 2hkoed by Hurricane + Fire Blast, Gastrodon is 2hkoed by Hurricane, SpD Heatran is 4hkoed after SR by Hurricane (w/o Protect factored in) and he can't do anything back except from phazing you, max HP Latias is 2hkoed by Hurricane after SR, even if he uses CM the next turn, Jellicent and Tentacruel are 2hkoed by Hurricane and this is it i think. (all these calcs assume rain up).
Not to mention that Moltres can counter QD Rain Volcarona if SR isn't up, and Volcarona in sun too probably.
Here are some calcs:
- +1 Lefties Modest Volcarona Hurricane vs 4 SpD Moltres: 78.5 - 92.52%. (by using 48 HP evs you always live after taking LO damage and a Hurricane)
- LO Moltres Hurricane vs +1 4 SpD Volcarona: 111.89 - 131.83%
- LO Moltres Hurricane vs +2 4 SpD Volcarona: 84.88 - 100.32%
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