P: Custom sort order of keywords (instead of alphabetic).

I just discovered this issue, and it's extremely frustrating. The entire purpose of hierarchical metadata structures is to create relationships between metadata. To then strip those relationships on export is to remove substantial value/usefulness, and is an absurdly bad practice from a records-management standpoint.

My use-case for Lightroom is admittedly an edge-case*: I use it to manage the photographic output of inspectors on a large-scale public works project. I have thousands (approaching tens of thousands) of photos to manage from a dozen photographers, and thousands of project-determined keywords, many of which are numerical and only meaningful in the context of a hierarchy.

I now have the task of exporting all this data to be worked with in other contexts. I've built considerable redundancy into my system at the filename/folder level, but to allow you to build hierarchical relationships and then not preserve them on export is akin to if Excel allowed you to build a spreadsheet full of formulas to manipulate your data, but only allowed you to export the formula inputs, not the outputs. The inputs have inherent value, but the relationships between them can allow you to create significant, sophisticated value.

(*You'd think there would be a bunch of software solutions for my use-case, but there really aren't. Most projects like this still manage their files by dumping them into Windows Explorer and then just changing the filenames to something descriptive and hoping for the best when you need to find something specific later on. Lightroom was still the best solution within my budget.)