As far as I can tell, no other catcher in baseball is catching this much. Yadier Molina (a much better player), for example, got lots of ironmanish praise for catching the day after the Cardinals 20-inning marathon against the Mets. However, Molina has only caught 88% of Cardinal innings this season. Matt Wieters has caught 88% of his team's innings as well. Other guys, like A.J. Pierzynski (not a bad comparable to Kendall) are closer to 80%.
Like Scotty Pods, Kendall started the season hot, and has since cooled off considerably. In his last 16 games, Kendall is hitting .232/.317/.268. He's not a "hot bat" we have to keep in the lineup.
The Royals just happily send Kendall out every single day and I don't see what anyone is getting out of it. Brayan Pena needs to play. He doesn't have to become the primary starter, but he needs to at least start catching more than once every two weeks.
Moreover, considering that Kendall is signed to a two-year contract (I know), the Royals might want to work on preserving this great asset as best they can.