It seems Blizzard fixed this issue in the 4.2.0a bugfix patch.You can still use LibStringStorage to reduce static memory usage and loading screen length, as well as saving a bit of HDD space with your SavedVar files.
LibStringStorage is designed to circumvent a limitation of the Blizzard SavedVar system - the SV system only allows a maximum of 2^16 lines for SavedVar files, and creates a new line for every table key-value pair. Some addons - especially logging utilities - often run into issues with this cap since all SavedVar data will basically be lost when the cap is reached (as the client will run into a syntax error when trying to read the cut-off file).
LibStringStorage avoids this issue by encoding tables into single-line strings with very minor overhead. As there is no limit to how many characters a single line can have in a SavedVar file, this allows up to 2^16-2 tables to be stored in a single SavedVar file.
See the API page for details.