I’m a few years late, but if you open the inspector there’s a little box at the top of the transform settings. If you click it, it’ll bring up a bounding box for your layer with a center point.
Also, the x&y coordinates can be treated like sliders. You don’t have to type in a value. If you click and drag on any of the numbers in the inspector they will change as if you were using a slider. It’d still be nice to be able to move the anchor point with your mouse, but I’m currently in the middle of a project that involves doing this a lot, and it hasn’t been that bad.