User blog comment:BIA-Kaboose/The Problem Behind Balance/@comment-5605969-20131211161837

Balance is something that in LoL will never be achieved (imo). Reasons are: there are WAY to different playstyle champions and not all of them possess skill-reward mechanics.

Take a look at one of the most balanced champions in game: lee sin. He rarely received nerfs or buffs after release and has a good professional history. This is because his kit is so balanced. But his kit also let's him do outstanding plays that many champions cannot, scaling with player skill. And that makes Lee a threat or a joke.

The cause of LoL's lack of balance is, as one said before me, Fake Balance (where you try to balance A with B, but one has a stronger effect, making it dominant), and Perfect Imbalance (a trick used by many games. By making A slightly better, or even introducing A, people will start using B to try and deny A's presence, making B dominant, and forcing players to get C or D, and since A conters C and E counter D, it helps to refresh the champ choices)

This makes more versatile champs more dominant, and more specific champs more "seasonal".