Doesn't the basing of ethics on virtues just move the goalposts? Unless I'm reading it wrong, we still have the problem of selecting Virtues. If so, is knowing which Virtues to embody a virtue in itself?
Virtue ethics are not proposed as a solution to defining what is good. Rather, it is in contrast to, for example, (direct) utilitarian ethics where it doesn't matter what virtue you may or may not be following; all that matters is outcome.
Virtue ethics spares you from considering all eventualities, and instead says: it is good to act like so, even if things don't always turn out the way you'd hope.
Both virtue- and consequence-based systems have problems in objectively defining what is a good virtue or good consequence (and how to measure it, if needed).