V1 is being used for two different things - 'good-to-go minus one engine' and 'committed to take-off'. For low take-off weights and long runways these are often nowhere near the same value. Why has it evolved this way? Why can there not be an extra parameter in the take-off litany?
V1 is not a rule, it's a guideline for judgements.
It makes little difference in how hard you set it. The outcome is subjective (statistical)
As an example the incident/accident rates for takeoff aborts are typically calaculated for anything over 100kts, since the data gathering is unsure exactly when the pilot decided to start the abort.