When iOS first launched, some of the brilliance was in how UI elements transformed into one another—a title in the title bar becoming a "back" button on the left, for instance. There were no intricate morphs, just a simple cross-dissolve between two elements shown briefly at the same time. It read as meaningful without being literal.
The Crop/Adjust example doesn't hold up here, because the two modes don't share a focus. The crop animation is deliberately different: it emphasizes the cropping controls at the edges of the image that you might otherwise miss, prepping you visually for the task and tying the controls into the image workspace. Adjust mode has no direct controls on the image itself, so the transition out should differ. The mismatch is the point, not a flaw.
For most UI, you don't need pixel-perfect morphs between small elements. The real job of animation and behavior is to convey meaning and context. Make your transitions pixel-perfect and most people would never notice the difference.