Hi Milardo,
I used my own dshow player before mpv and first I wanted to improve it but it's a huge task to built a complete player almost from scratch so I evaluated all options for a while and mpv is what I liked most in the end, for mpc I would have needed two years to become fluent in C++. In case somebody wants to build a dotnet dshow player my code is here:
https://github.com/sharp-player/sharp-player
mpv probably won't support dshow, for some time I thought about having two playback engines, like dshow and libmpv, it could be done and might make sense but only if you have a lot time and interest, in StaxRip normally I try to support different encoders, it supports both avisynth and vapoursynth equally well and I'm very happy with the decision to support vapoursynth. Doing a player with two playback engines is much more difficult I think and most players don't get it right even with only one. I don't have enough time and interest for both so I decided to focus on one and make the best out of it.