Powers in Champions Online vary widely in the eyes of the playerbase. Some powers, like Mind Lock and Arcane Vitality, remain mostly unknown, while other powers, like Regeneration and Haymaker, take center stage. Sometimes this reputation is due to a present or former imbalance like Collective Will, and sometimes it's due to an unknown combination of factors, like Roomsweeper (probably because Might is the most played powerset in the game).
And sometimes, like in the case of Gigabolt, it might just be something else.
Powers are balanced in CO according to a variety of mathematical factors, such as activation time, range, energy cost, and damage dealt. But the devs also try to have their powers balanced around another factor: Fun. On a 1-10 scale, most powers in Champions hover around a 3-4 on the fun scale, with the standout powers pushing up to a 5-6 and possibly as high as 7 or even 8 for good synergies between several powers. When a power gets too fun, like the Incisive Wit advantage for Kinetic Darts, the devs make sure to issue a patch to fix the imbalance.
Except for Gigabolt.