whatever, your blind, you see what you want to see. Installing EVERYTHING just shows how little the core has to offer. It would also confuse a newbie. You failed to address tutorials, and help forums. Who is going to teach a noob where things are to -x them? Who is going to show them where repositorys are? who is going to show them how to find apps they want to use? Who is going to show them how to configure those scripts? WHo is going to explain to them even what a freaking daemon is?
Also, I hae used Gslapt, and it is not in the same league as Synaptic in terms of what you can do. It would work, but they would have to setup atp repositorys and then know to use that program. Ubuntu use synaptic and apt by default and shows how to use it. Also dependancy resolution is still a pain in slack. You will run into it if you want to use something that slack doesn't already give you (this is the reason I use gentoo). Slackwares supported and default package managment is tarballs. That is still a pain.
So answer me this. Gentoo is easy to install (just follow the instructions right?) has great package managment, a great user forms and howto docs. I think it is the best noob OS out there. Wouldn't you agree?
I love gentoo. But I recongize that noobs need hand holding. They need massive help. Slack, gentoo, and the like do not provide that. SuSe has that (yast is great for noobs). Fedora has that (yum is easy for noobs and fedora has a lot of noob forums and support) Ubuntu is great for that (Ubuntuguide.org will give you a great desktop, ubuntuforums.org will help answer any problem, no matter how trival).
Slackware still uses 2.4 kernels. This makes hardware detection on newer hardware a little worse. Some users will have to take manual steps to get their hardware working. As far as I know slackware still does not have a automatic update system or more importantly automatic security updates. Noobs will not be smart enough to watch security advisorys or to even update themselves. FC, suse, ubuntu, etc have automatic updates that can run without user intravention.
Slackware still uses lilo bootloader as a default. This can be a problem for people who want to run more then one OS. Lilo is very particular about where it is installed, grub is not.
And finaly slackwares release cycle is unknown. Packages can get old and out of date. Ubuntu has a fixed relase cycle with backports. This means users will not have to go download tarballs or source to get up to date software.
I wont deny slackware is a good OS. It is a good OS. In fact most linux distros are great if you have a foundation in linux. But it is not for beginners. Beginners need GUI tools, they need user support, then need automatic updates, they need massive hand holding while they learn what a console is. Or how to do something as trival as make X start with numlock on.
I understand slackware, I've used it. I found it to be a good OS. But when I was starting out, I tried them all. I failed on them all. My savior was suse with yast. Then debian as I started to want more control. Finally I went back to slack because I wanted to be leet. I learned what I wanted was not there. I went to gentoo because I wanted more control over my OS then even debain can offer, with the ease of a great package managment system with dep resolution. Slack could not offer that. So I have been a noob. And I know a thing or two about what it means to have your hand held. But arguing that slack is for noobs is like arguing that gentoo with a cron job that runs emerge --sync && emerge -uD every 24 hours is for production level servers. Each linux OS targets a user base. Ubuntu targets linux for normal people. Debain targets the open source crowd that craves stability. Gentoo targets power users and ricers. Slackware is a power user distro.
I the end it comes down to what a user is comfortable with. Most users switch linux distros like wild fire when they start.
Mepis, Xanadros, Suse, Debian, slack, FC, etc. Every OS has its own strenghts and weakness. I could list a million things that ubuntu sucks at, and come up with a large number for FC, suse, gentoo, slack, etc. But I do strongly feel that suse and ubuntu have made the largest inroads to a normal user using linux.