I recently spent some of my spare time attempting some code clean-up and improved consistency as regards using Region.SEPARATOR instead of hardcoded "/" in region names/paths, and have the changes up for review here: https://github.com/apache/geode/pull/5049
It'll be a very tedious process, but if anyone would be willing to check it over and approve it (or reject it, if there are problems with it I haven't foreseen) I'd be very appreciative. I should also point out that this wasn't an attempt to replace ALL uses of hardcoded slashes in region paths, just those occurrences where the "/" string is used. A second pass to replace all uses of slashes in region paths with the Region.SEPARATOR constant may follow if I'm feeling particularly masochistic one weekend.