1. Bugs are fixed in KDE, but it requires somebody to step up and do it. Just like any other open project without the resources of large software houses. You should rather stick to your complaint on the over-stretching/re-designing part.
2. Agree to some extent. KDE has in periods over-stretched the resources, and various projects should have been less ambitious in favour of getting things done.
3. The documentation is good, but I agree, we should improve it. KDE has a wiki, so I suggest you and I help out.
4. KDE uses git and cmake, it uses the best VCS and build system around. Actually, your last point here makes me wonder if you are trolling, have you even read the KDE documentation?
KDE follows that standard modus operandi for cmake and git, you do:
git clone git://anongit.kde.org/yourprojectofchoice
If this is beyond you, I suggest you stick to binary packages.
Any missing dependencies will typically be reported, you can for instance use tools in the debian-goodies package to track down which package name your distribution uses for the missing dependencies. Typically, you will have a very smooth experience building bleeding edge KDE on the latest Kubuntu.
Reporting bugs in KDE is a very smooth experience. Just about any project has a lot to learn there. It is rarely a problem to identify the package, and a number of volunteers come to the triaging rescue if you produce crappy reports. I believe it is exactly the kind of criticism you give here that frustrates Aaron. It certainly frustrates me. If you have a point, make it. Quit the inaccurate bashing. KDE is an excellent project. We should be grateful, and we should show it.