Before revision:  That same regression model quantifies the short term value of the treatment allocation and this comparison favors smaller \Delta with the RDD being best.
After revision:  We point to additional advantages of tie-breakers versus RDD: for a nonparametric regression the boundary bias is much less severe and for quadratic regression, the variance is greatly reduced. For a two line model we can quantify the short term value of the treatment allocation and this comparison favors smaller \Delta with the RDD being best.