http://bugs.winehq.org/show_bug.cgi?id=34045
--- Comment #11 from Vincent Povirk madewokherd@gmail.com 2013-10-05 15:39:40 CDT --- My understanding is that MS's directx assemblies, which are installed by the directx redist, work in Mono, and .NET doesn't include them either. So, I believe Mono and .NET are equal here.
We could provide an open-source replacement for those assembles with Mono (and it is probably not difficult if you know a bit of C#), but I don't personally plan to work on that. If you want to do this and need help getting started, let me know.
Or is there some other Mono bug I'm not aware of?