Don't know if it helps, but, even though GL_ARB_direct_state_access isn't supported in current drivers (15.4b), GL_EXT_direct_state_access works just fine and I haven't had any compatibility issues with it (yet).
I have a basic DSA wrapper that uses the appropriate function calls depending on the build (4.4/4.5), and aside from passing a target parameter to functions and settling for glGen* functions instead of the shinny glCreate* ones, it doesn't stop me from writing a 4.5-like codebase.
R9 290 + EXT_DSA and 760 + ARB_DSA produce the same results so it might be worth giving it a try.