In older versions the tab where you could define gradients had an option to load and save a gradient palette. That was removed. But now there exists no way to load a gradient palette. For colors a drow-down list has been introduced to use different palettes. A similar tool is missing for gradient palettes. LibreOffice still delivers the palettes "classic.sog" and "modern.sog" besides "standard.sog". But you cannot use them, because you have no access to them.
We intentionally removed the load/save functions and deliberately cleaned up the UI. If those functions should come back it has to be as an extension, in my opinion. OTOH, I could live without those sog files.
Defining palettes can be done in an extension. But gradient and hatch could have a drop-down list similar to that used for colors, which shows the existing *.soh and *.sog palettes, both from share and user, and a list item for the definitions from the actual file.
an option to select a set of gradients/hatches, as is offered for color palettes, doesn't seem an increase in complexity of UI or program, that we should be afraid of. So IMO a sensible proposal.
The complexity is definitely increased with such a modification. Switching between gradient "palettes" via dropdown leads to all the trouble we have with color palettes in various places. In my opinion we just have to allow "loading" of gradients per extension, which adds those to the list of presets. But in the discussion here and at the design meeting my concerns have not been shared by others.