Agree with climbs-like-a-dog except for No.4, you can't supervise somebody whilst they're in the air, so I see little point in doing it on the ground.
The currency and biannual check requirements which came in with JAR-FCL should be quite enough.
If you'd care to compare airmanship Irish, I had a PA-28 turn at 900ft across a town straight towards me 2 years ago whilst I was flying S&L down the coast in a microlight (line feature on my left of-course); I had to do a rather steep descending turn to get out of the way. 40km viz, when the airprox board had a word with the chap he said he hadn't been looking out because Prestwick (40nm away, nearest class D about 20nm) hadn't reported any traffic to him. I had been watching him for 5 minutes (throughout which I was flying the same height speed and course), he claimed he only saw me as a I flashed past his window!
On which subject if you were at 1500ft in VMC, how could a microlight "flash past" without warning given it is highly unmanoeuvrable and probably flying at 45 knots? If memory serves, Exeter CTA is 5nm across, so at 4½nm out, he was 2 miles outside the CTA.
I was mostly trained by the queen in Bulldogs then jets, but I fly these things for fun and professionally, and I fly with a lot of people trained only on this low hour license - the standard is generally very high. I also know a few idiots, one or two in the league of the PA-28 pilot; I think regardless of training some people will just forget it all and do their own thing - which is where the currency and biannual check come in. I can't see why a similar treatment won't work for simple 2-seat light aircraft.
G