Good question, and one we have grappled with quite a bit. The key factors for limiting the number of series races are as follows:
To give runners that want to contend for a Championship or Age Group title a higher probability of head-to-head competition;
To give runners who want to earn the distinction and recognition of being named a RUNColumbus Road Race Warrior a realistic shot at doing so; and
To maximize exposure for the races that are part of the series each season.