post-it... no. Just... no.
What you said is wrong in many ways, and you're just going to confuse KaseiHikari. It is not true that "no codec should ever need help from another program to load stuff into an editor" - most codecs weren't meant for editing to begin with, since afaik there are many more lossy codecs than lossless out there anyway. Hell, even DVDs and Blu-Rays aren't meant for editing since they store lossy video. Avisynth wasn't meant to be just an help to load stuff into an editor, its purpose is much wider than just that.
Also, the answer, imho, is still avisynth+virtualdub, which btw is continuously updated (latest version is v1.9.9, released this April)... and even if you wanna use Avidemux (which isn't quite as good as avisynth for processing, if you were to ask me), the latest version is 2.5.2 released December 2009... not exactly old.
Furthermore... never treat codecs and containers as the same thing. They are not.