See Preferences / Tweaks:
- Number of columns for custom metadata in the edit metadata dialog (ID: metadata_single_use_2_cols_for_custom_fields). Change it to False.
- Edit metadata custom column label width and elision point (ID: metadata_edit_elide_labels). Make the numbers large enough to see what you want to see.
One of the other edit metadata layouts in Preferences / Behavior might be more to your liking.