[Cerril]

Well the first part is sample size. In order to get any meaningful numbers you're probably looking at several tens of thousands of hands.

Additionally, WSD and W$SD are notoriously difficult to analyze. Running good, bluffs, ultra passive and ultra aggressive opponents make massive changes to these numbers over the course of time.

That said, I'm fairly sure there are some optimal numbers given other stats, but I couldn't tell you what they are. W$SD and agg on river are composite numbers, made up of bluffs, value bets, bluff catching, too passive opponents, and so on... Style is also hugely important. A more LAGgish winning player and a much tighter winning player will probably look pretty different here.

However, with a low AF, a high W$SD, a low river agg, and a high sample size, you can probably see a need to show a little more aggression on the river. Whether that means you're giving up too many turns, or too many rivers, or just checking behind too much is sort of up to an analysis of what you've found yourself doing a lot of.

edit: One goal may not be to equal 50% any more than your goal for W$SD is 50%. I've got a 51.5% W$SD and a 55% product of the two terms you discussed. I'm thinking there'd be a problem with a large disparity there, but if they're fairly close together it isn't an obvious problem.