I'm with Pace on this one. It's not the engine stopping that will teach you anything, it is what you do to deal with it. Light singles will land very nicely with the prop stopped. I may be biased here as a glider pilot as well as power, but I do get to fly with a lot of people with an unhealthy dependence on the engine, in particular by flying circuits more akin to a major cross country, and a final approach which in the event of an engine failure would ensure a crash.
We are not teaching people to fly but to drive, and do them no favours at all, if we teach utter reliance 100% of the time on the engine.
Forgotten techniques? Height can be lost very easily but it's rather hard to claw it back on approach. Let's try to find some more time to teach sideslipping and s turns, pilot navigation with map and watch, forced landings with power that result in an undamaged aeroplane, short field and soft field techniques, flapless landings, flying without instruments, care of passengers, and above all some feel for what the aircraft is doing.
Maybe we could find this time by losing the big aeroplane mentality, the 747 circuits, the faffing around on the radio, and in general the implication that all students will go on to fly airliners. They won't. Anyone training for that can learn the appropriate techniques when they transition to large aircraft. The rest of us will benefit from handling a light aircraft as just that, eyes outside and fly the attitude.