Maybe, but I get the impression that overall the addition of a true runoff tends to make things better. For example, this guy compared a number of voting methods using his preferred metric, Bayesian regret; note that when a method and a variant with a runoff added to it are compared, the runoff tends to do slightly better: http://rangevoting.org/StratHonMix.html

In addition, I have no data for this but I expect that a runoff would increase the perception of legitimacy of an electoral result, because while the initial voting procedure that narrows the field to only 2 candidates will occasionally be impacted by counterintuitive results such as spoilers, at least the runoff can always be interpreted in a straightforward manner as "we were choosing between A and B, and most voters preferred A over B".