The offline tool has the same functionality as PlugY. It even saves the shared stash in the same file format.
Yeah i'd prefer shared stash like it used to work with PlugY in the game (also PlugY bonus stats pages) but it is what it is. You can still play Median 2017 or any other Median version for that matter.
I don't think this will work. Current Median is developed with realm play first and foremost. This is in stark contrast to what Median XL used to be, a SP mod before anything else. First major realm for Median XL was D2 Maniacs and that came long after original Median XL release in late 2008.