Has anyone attempted to make an independent DShow environment so that one could use a DShow-based player like MPC-HC (I saw that there was work on the player, but AFAICT, it depends on the host for codecs outside of its limited built-in capabilities)? VLC and SMPlayer are fine for low-resolution videos, but I'm pretty sure neither has an AVC decoder that supports any kind of offloading to the video card (ffdshow supports DXVA, CoreAVC supports CUDA and is extremely optimized overall, etc.). Granted, it's far from guaranteed that the average user will use hosts with video cards that support such things, but it certainly puts playing high-quality, high-resolution AVC-encoded videos into the realm of possibility for some users. This would also make a portable AviSynth possible, which would be awesome for those who want it.
This is more of an idea I'm throwing out there out of curiosity rather than a request. 
Hmmm... It seems possible. MPC-HC can store all of its filter information and such in an INI file, and the paths can be adapted... I'm not seeing anything left behind in the registry from ffdshow-tryouts either. I couldn't try using CoreAVC as I'm a poor student, but if the MPC launcher did the registry entries right then there's no visible reason why it wouldn't be portable.
But there’s no sense crying over every mistake,
You just keep on trying till you run out of cake.