As you mentioned with the load and slew option most of the use case will be covered. The feature described by Croz is a powerful feature that is available in NINA preview. Prior to moving to kstars I used NINA and the framing assistant did this. I used this extensively to reduce the no. of panels required when planning a mosaic. My workflow was:
1. during the day I entered the coordinates or the target I wanted to image and press the load button and the target was loaded on the right hand side.
The box over the image represented the sensor field of view. (note the image source on the top had the option of loading a file and plate solving similar to what feature that we are looking at)
2. On the target section the user can add panels and set the rotation required. The is particularly helpful as it allows me to reduce the number of panels required.
3. Once I am happy with the panels I press add target to scheduler (sequencer in NINA) and panel one and two are send to the sequencer where the no of light frames and dithering and autofocus etc. can be selected similar to kstars.
In my astroclub this is a typical workflow for most users.

Framing live as you have mentioned is no issue, but sometime time consuming when you include setup, pack up manual rotation and manual filter change etc..

But.. thanks heaps for working on this feature this will solve a lot of issues for users like me and increase our imaging time.