Just to be pedantic; none of the "*D3DX*" stuff was ever part of D3D, it was part of D3DX (a closed source utility library made by MS to make some D3D tasks easier to get started with). What's happened is that support for D3DX has been dropped, so there's not any new versions. Instead, we now have some open-source utility libraries filling the void. AFAIK, DXTK is open source but also officially endorsed (and worked on) by Microsoft.

It seems like Microsoft made things more difficult to work with DirectX from version 10 on. Is this the reason so many people are still programming for version 9.0c?

Difficult? I started with DirectX 11 as I find it really easy compared to DX9.x stuffs.

DX11 programming is similar to DX10 progamming, with some exceptions (device vs context) and new additions (tesselation pipeline, compute shaders, deferred context and multithreading, dx 11.1 and 11.2 extensions), but most is just simple refactoring (from 10.x to 11.x), you can even use feature level 10.x and SM 4.0 profiles.

If you feel frustrated do D3DX removal, have a look here: http://blogs.msdn.com/b/chuckw/archive/2013/08/21/living-without-d3dx.aspx