Not really. Pokemon like Metagross, Salamence, Garchomp, Dragonite, and Tyranitar have higher base stat totals than any of the legendary trios. The trios add up to 580 while those guys add up to 600 (like Mew, Celebi, Jirachi, Manaphy). The ones most people ban outright are the ones who have a stat total over 600 + a couple of the 600 ones.finalozzo said:ah Choice scarf XD, right. Anyway firestorm: are not all legendaries with high statistics?
Then you have Pokemon like Moltres and Articuno who, even though their stats total up to the 580 which is decently high, have terrible typing / moves / high stats in the stats they don't need / whatever.
Legendary is just a designation for the Pokemon fiction. Don't get hung up on it and instead look at Pokemon for what they can do in a battle. Just looking through the tier list:
Ubers (banned)
Everything else
http://www.smogon.com/dp/tiers/uber
OU (used a lot because they're good)
Azelf
Celebi
Heatran
Jirachi
Rotom-C / F / H / S / W
Suicune
Zapdos
BL / UU / NU (not used very often because they aren't too good)
Cresselia
Raikou
Shaymin
Moltres
Mesprit
Regirock
Registeel
Rotom
Uxie
Articuno
Entei
Phione
Regice
Regiggas