Are evil wizards more poweful that non-evil wizards?

[Pleh]

Continuing on with this new dark/light side of the force conversation,

An entire order, hundreds of "good guys" could not beat two "bad guys" They played both sides, eventually resulting in almost every single member of the Jedi ended up dying. TWO "bad guys"
Also, from what i've seen in alignment in the movies:
Light side: neutral
Dark side: neutral
Sith: Evil
Jedi: Evil
Rebellion: good
Empire: evil

Double edged sword. Two sith with unlimited resources couldn't kill more than 1 out of 3 jedi 20 years later.

Might be more an issue of, "don't try to kill a mosquito with a cannon" than dark>light.

Also, Rogue One really draws into question your assertion the rebellion was Good and not merely Neutral.

Edit: yoda in the prequels and Luke in the new trilogy both kind of insinuated the fall of the order (both times) was personal hubris. Not a weakness of the light side, but user error.