Most of the WM packages are converted Slackware packages. They don't show up on the gdm menu because Slackware doesn't include gdm. Those packages really need to be rebuilt to Vector Linux standards. PekWM is a notable exception because I packaged it and Vectorized it. I had planned on doing the same to most of the others but doing work I actually get paid for got in the way
It's still on my to-do list. nightflier is correct: it's time consuming. Hopefully the ones you want will be in testing soon.
I would expect *any* distro with Xfce to be slower than all but the most bloated distros with IceWM. Xfce has become a full blown DE. It's still not nearly as bloated as KDE or GNOME but it is getting there. LXDE, as you pointed out, is very much a work in progress upstream. On my old, slow hardware I'm running PekWM + fbpanel + pcmanfm + VL-Hot to make a decent desktop that's pretty darned fast. Remove pcmanfm and use Xfe as you suggest would be even faster but the vl-hot/pcmanfm integration is nice.
understand complaints about desktop artwork and themes. That is always a matter of individual taste. How hard is it to right click on the Xfce desktop and change a background or a theme? You don't like any of the themes? Make your own! It isn't hard or particularly time consuming and it will be portable from one distro to the next. I happen to like the 6.0 artwork and theme but that's me.
Your complaints about the installer are certainly valid. There are broken parts you clearly didn't run into. The next release should include a translation into French if and when I find the time to do the translation. Seems I'm the only volunteer qui parle français. C'est dommage.
Thankfully I have native speakers in my family so any humorous translations will get corrected before being submitted
In any case a new, improved version of the installer is already in development.
re: gxine: post a request in the Package Requests section of the forum. We do have more volunteer packagers than ever and requests are getting completed rather quickly.
All in all most of your complaints are things that should get sorted out in the near future without having to wait for a new release.
Oh, didn't you give up on Linux, declare it to be garbage on the desktop, and move to all Windows?