If it wasn't for the output quality issues WMM has, I don't see why people slam it so much. It does most of what you need - albeit I suspect it has trouble opening AVISynth files but I've never tried.
People who think they need Premiere to do everything are just plain wrong. Sh1t, Hsien used to use Ulead Media Studio Pro for everything, and he made some really really kickass videos. Half of my videos could be made using WMM or Ulead or Pinnacle Studio 7. You don't need Premiere for everything... in fact I think sometimes it'd be better if everyone wasn't given the options that Premiere gives them because 97% of the options in Premiere shouldn't be used in a music video (read: snazzy transitions, stupid filters, etc).
Things like the replicate filter. I _hate_ that filter. The only time I've EVER seen it used right is in Shameless Rock Video, every other time I've seen it used it's been trite
and detracted from the video.
Premiere is a very very powerful tool, and many of the things it does are truly technically impressive, but most of the time you don't need them. If you gave me a video editing tool that could do multiple tracks with transparency, had only the Crossfade filter, and could work with my DV500 in realtime like Premiere, then I would use it, because it would pretty much do everything I needed. WMM comes close to having what everyone needs, it's just held back by some video quality shortcomings from what I've seen.