In no way! William O'Neil's books are great and got me hooked in the first place. I actually label myself as a technical fundamentalist or technofundamentalist. However over the years I realized that you have to look beyond the CANSLIM 'frontend' with all the labels and 'simplified' rules. While I rarely buy any of the CANSLIM chart patterns I am always aware of them.
One can argue that in todays age of instant information base breakouts are late entries. The mass psychological mechanics behind the patterns are still sound of course but you have to make sure that a pattern isn't too obvious.
Tight weekly closes are golden and are often the breeding ground for my favourite quiet and tight swing entries.