From personal experience, Adobe applications have never worked on case-sensitive HFSX. Also with the legacy compatibility layers OS X shipped with up until 10.6

From personal experience, Adobe applications have never worked on case-sensitive HFSX. Also with the legacy compatibility layers OS X shipped with up until 10.6, there were enough expectations on case-insensitivity that it was probably easier for them to just not risk a bunch of legacy apps not working anymore. And by the time 10.7 comes along there's enough momentum to just leave it alone. Their focus now is on Core Storage (an LVM like thing that doesn't have 1/2 the features of LVM), to the degree that now in 10.10 it's the default for both upgrades and new installations. So FWIW these volumes are no longer read/writable elsewhere like on linux or Windows.