I don't think the stats prove anything either way. If, however, you're trying to defend Laidley's reputation here, then the stats certainly don't corroborate roosurgence's view. Hard to say what Pagan might have done with Harro over the years he played under Laidley. Fruitless task I would suggest.
Those stats so show, however, that Harro's winning %age (67-2-63 or 50.8%) was higher than Laidley's (48.3%), during Laidley's tenure (72-2-75).
We will never know because Denis went chasing the big bucks at the Blues.