There is plenty of lack of execution to go around. I don't know about Castro. His release point is all over the place. His mechanics will have to be more repeatable for him to have sustained, consistent success. I don't know if changes there would rob him of his velocity and explosive movement, but the current version isn't going to work.
I see some similar problems the last couple of nights to the sloppy play in Buck's last year that set me off. Baserunning errors where we get late break to a bag because we aren't fundamentally sound on rounding bases aggressively and watching throws relative to the cut off. Guys missing signs (perhaps intentionally) and missing an opportunity to get down a sac bunt, then getting the sign (overtly) and giving a half-assed bunt effort to go down 2 strikes. Failure to take an approach to move runners over in close games. Of course, failing to cover home and letting 2 runs score on a past ball.
I can deal with having a rebuilding team that is a little bit down in the talent department, but there is no excuse for those guys to not be executing fundamental baseball. I'll watch developing players or even overmatched players play, but I'm not going to watch bad baseball.