Actually Vaporeon speciality is HP and through decent Special Attack (which is better than its Attack) Jolteon, Espeon and Glaceon all have higher Special Attack. Without look at Serebii...i'm sure that vaporeon's base Special Attack is 90, which while at least above average doesn't made "one of the best out there" in Terms of special attack. Plus I wouldn't conisider them Legendary, maybe in total base points but a few of them suffer (especially Flareon) from poor or limited movepool. Not saying they suck, but they are not considered as strong as many think.
But totally agree on the 1st point