Bioware had the potential to create the Star Wars of videogaming with this series.

However, they didn't stick to landing and as a result the series felt like squandered potential.
In the end, the mystery of the reapers, this massive civilization of AI constructs was revealed to be a countermeasure so that organic life can never create AIs capable of wiping out organic life.

Let me repeat that: Someone create a bunch of AIs so that they would periodically wipe out organic life to prevent them from creating AIs capable of wiping out organic life.

Yeah...