J-stroke recovery is with vertical blade
For a minute I thought you were disagreeing with what I wrote, largely due to the title of your post, but after pondering your words, it seems to me that you are suggesting use of the same type of correction that I was describing. I agree with you about the pivoting action of a paddle blade too, where even though it can be pulled from the water cleanly, the top and bottom ends of the blade are "fighting each other" as the blade angle rotates. That's more of a blade-efficiency thing than an issue of "drag" though, since the net force applied by the blade can still be toward the rear as this is going on.
A blade that's vertically-oriented as viewed from the front or rear of the boat, thus knifing through the water, can apply a sideways push while producing force with neither a forward or backward component (so the only drag is the knifing action itself, and that's tiny). While the blade is curving into position to make that sideways push, there's both a rearward-pushing component of force and a sideways-pushing component, but unlike during a ruddering-type of correction, there's no forward-pushing component, and thus no "drag" of the type that people usually are referring to.
Anyway, though I'm not a bent-shaft user, I can see that it could actually be easier to get an efficient blade angle during correction at the end of the stroke with a bent than with a straight.