Suggested feature: The smplayer/mplayer/readme.txt claims that it is shipped with mplayer AND mencoder. Please do not remove mencoder.exe in the SMPlayer distributions.
Background (long story): The one thing I like in MPlayer is its documentation (two HTML files), because it explains stuff not covered in the lousy FFMpeg documentation. Example, the two swscaler parameters to pick another bicubic algorithm exist in FFmpeg with almost no documentation at all, but the MPlayer documentation tells me what it is (or at least enough for a Google or Wikipedia query ;-)
If I'm still lost I have to test it, and at that point I might need mencoder, until I figure out how to get the same effect with FFmpeg. OTOH I do not like the Windows MPlayer, it wastes minutes to scan my Windows fonts, always expecting to find a new font for subtitles I do not have in a script I cannot read. That's the main reason how I ended up with SMPlayer as "third opinion" (= WMP and MPC-HC already failed, but FFPlay can do whatever it is.)
SMPlayer doesn't use mencoder at all so I don't see any reason to include it in the SMPlayer packages.
You can always get mplayer packages with mencoder here:
http://mplayerwin.sourceforge.net/
About the problem with scanning fonts, you can try SMPlayer with mpv. Recent versions of mpv don't use fontconfig on Windows anymore so the problem should be gone:
http://smplayer.sourceforge.net/mpv
Last edit: Ricardo Villalba 2015-12-30
Yes, at some point I should test mpv, maybe when I'll update "mpv (media player)" on enwiki again.
Newer versions of mplayer have fixed the problem with fontconfig as well (requires at least windows vista).