In Photoshop, which has a more similar approach to Aseprite compared to Animate, the Transform tool gives you scale and rotation input boxes in the toolbar instead of doing a pop-up, which also auto-update as you rotate the transform handle. So, for example, you can rotate loosely to get an approximate value (e.g. to figure out which multiple of 10 degrees you need), and then tweak the exact value.
Aseprite already relies on toolbars in a similar way, and I’d love to have something like this added to it.
The various toolbar items are, from left to right:
Pivot anchor (similar to Aseprite’s except as a clickable thing rather than a menu since PS has the space for it)
Pivot location, X and Y (for moving the selection; the triangle can be clicked to toggle whether this position is listed as absolute in the canvas, or relative to the starting point of the pivot)
Scale factor, Width and Height
Skew, Horizontal and Vertical (I don’t think this feature exists in Aseprite, but scale+skew is great for converting orthographic images to isometric!)
Also, along with Rotate 180/90 CW/90 CCW, PS’s Rotate menu gives you an “Arbitrary” option which does just pop up an input box:
(this one is for “Rotate Canvas” only because rotating selections arbitrarily in PS requires using the Transform tool, as described above)
I think this sort of option would be a nice addition to Aseprite’s Edit>Rotate menu.