I hope you don't mean that checklists aren't necessary
There is a place for checklists providing they are concise and not so full of superfluous items that pilots skip reading them.
In the case mentioned it was clear the Islander pilot who claimed check and training time on type was so reliant on the checklist as a crutch to lean on that without it he had no idea how to fly the aeroplane.
The basic scan left to right for before start and after start checks in ab-initio aircraft such as Cessna and Piper singles, is essential knowledge before first solo. For example, I was once given a student who already had 10 hours dual on a Cessna 150 and had yet to go solo. After we had settled in our seats, I asked him to go ahead and start the engine.
He apologised and said he had left his checklist in his car. I said that's OK - you don't need a written checklist to fly a Cessna- just use scan flow. The poor student admitted he hadn't a clue how to get the engine going because his instructor had always used a checklist even for a pre-flight inspection.
To him the written checklist was a crutch. After he was shown a left to right scan we got airborne but not without a delay because he did not know the pre-take off checks unless he had a written checklist.
After landing, he taxied in and was embarrased to admit he did not know how to shut down the engine without a checklist. I felt sorry for him because he had really been left in the lurch by his previous junior instructors who themselves had barely 400 hours each. The blind leading the blind.
With airline aircraft, the required checks are made by scan and although numerous switches and gauges are checked during the scan, often the written checklist contains only essential items as a confirmation.
With light aircraft, it is important from the airmanship and pilot confidence point of view, that students and private pilots are competent to operate the aircraft without falling back on the crutch of written checklists. If a regulator demands checklist use then it should be only for the vital actions before take off. The operative words are
vital actions.
These amount to perhaps six items sometimes known as "killer items". These items are specific to the aircraft type. In that case, the pilot should first complete the items in a scan method. Then if required, refer to a written checklist to confirm those items have been completed. Rambling lengthy written checklists are counter-productive. Items get skipped because instinctively the pilot knows they are superfluous.