Allow controlling line height
Many fonts have glyphs that would go beyond line height and currently these are cropped. It would be nice if line height can be manually set for cases like these (no cropping would be good to, and man be optionally using the glyph bounds instead of the line height info from the font).
دے چكے ہين and Noto Nastaliq Urdu.

I agree 100%. At least half the things I work on can use this. It would also be useful if there were a visible line for the bounding box to be totally clear where things will get cut off. I test a lot in browsers and for certain scripts the default line-height needs to be set quite high so having that option here would be very useful.
You can more or less do what you want by going to the "Options" tab and reduce the "Relative Size" and fiddle with the "Baseline" slider.
Zooming with pinch zoom, or option-scroll or command-plus/minus changes the size of the "box".
Unfortunately, with the way the UI is built, it is currently not possible to not do cropping.
All of this together should certainly be reconsidered in a future version.
I missed the Option tab. That is good enough for me, thanks.
I will leave the issue open anyway as a reminder of things to consider if/when a bigger redesign is to be done. The fact that you missed the Options tab is already reason enough to consider this part of the UI suboptimal...