Con had some great ideas, no doubt, but he has a huge lack of objectivity which probably biased him and led to his current discontent.
For one, he describes a horrible performing desktop environment. However, we have been avid Linux users since the late 1990s and one of our justifications was that Windows felt slower on the same hardware. It was originally due to that desktop experience that our offices have been primarily Linux based since around 1999. Most people in our office dual-booted to windows/2000 (staring with beta) or later windows/XP and we always found the windows environment to feel slower than Linux, especially when we were running lots of applications at the same time. Everyone was given the choice to use windows or Linux and by the end of 2000 everyone found they liked Linux better on regular machines for regular desktop use. Starting about 3 years ago only a few of our machines even dual boot anymore, we just wipe windows off completely so we don't waste the disk space.
In the article there was a description of music skipping, windows jumping, programs running slowly, etc. That may have been true 10 years ago, but nothing like that exists anymore. Even on my 500MHz Gateway Laptop back in 1998 this was not an issue. It ran fine, played music, ran word processing, was a pleasure to use. It did skip when playing movies, but the rest was an upgrade from windows.
As far as the reimplementation, I think we need to be objective. Con has had awesome ideas and great insights and could prototype well, but his coding skills were still a bit behind some of the other core developers. He pioneered a great scheduling idea, which is the hard part, having it re-implemented and cleaned up is a natural part of software progression and one of the benefits of how open source works. Unfortunately he let that get to him instead of being thankful for the adaptation of his ideas, which was his ultimate goal in the first place.
These days Linux is a dream to use. My Linux laptop (Dell Inspiron 9300) runs fantastic. Its fast, I can have compilers, www servers, databases, number crunching applications all running and still have a very snappy desktop. If I compare it to Vista then we are talking about Linux being by far the best performer. Even if I boot into XP I feel I'm tapping my fingers waiting all the time, which just doesn't happen in Linux. Anyone who dual-boots will see that Linux feels far more snappy than windows on the same hardware, and I don't even have the new scheduler yet.
Clearly the Linux desktop is doing very well. I think the entire context of the complaints was a way for Con to let of some steam. I wish him well in what ever he decides to do and I'm sorry to see his contributions lead to bitterness.