Line styles should be able to be edited (via the Line Style Editor) when stored in DGNLIB files. Currently, they must be edited in an RSC file and then imported to a DGNLIB if that format is desired for storage. DGNLIBs are useful for storage because they embed element properties within design files upon placement, which is helpful for sharing files between users who do not have access to the same workspace. If line styles could be edited in DGNLIB format, it would remove the need for duplicate workspace files and simplify workspace management.
Custom line styles are stored in rsc files. If the rsc file is missing, those lines are just displayed as continuous lines. AutoCAD does the same with lin files. Having this as a ressource stored in a dgnlib and consequently as an internal source of the dgn file (just like levels) would requre a completely different approach, but legacy files need still need to be supported.
This is comparably to the transition from tags to item types.
Just like these the new line style ressource would meen a great improvement.