I agree with that 100%.

Because it is not what passengers want, is more trouble for the airline and would take more time.

Cut-price airlines (in Europe at least) are increasing hand-luggage allowances and charging for checked-in luggage.
If you have hand-luggage only you can often check-in later, and don't have to wait for your luggage to come off the plane.

Sorry, this one won't work.

I agree with ChrisF, too many people use the carry-on feature now. And with the present system flights still take-off and land on-time.

For security reasons only, I would like to see no carry-ons allowed and people are x-rayed using the low-power versions now available. That way it will catch even those ceramic knives terrorists have been using.

The present reduced hand luggage restrictions are causing chaos. The size limit of 55x40x20cm means you can no longer take on a backpack, only a slim bag. Many people (me included) have been used to day trips, or one night trips, using just hand baggage. I can no longer do this. This means I have to arrive 2 hours before the flight (instead of 30-45 Minutes for hand luggage only), and wait 30 Mins.+ for my luggage to come off the conveyor. a 1½ Hr. flight suddenly becomes 3½ Hrs.

Another problem is drinks. The one thing I absolutely must have as hand luggage is a drink. For years the airlines have been advising you that for medical reasons you should drink lots of fluids. Suddenly they are banning liquids.

There is too much paranoia here. The IRA didn't succeed in shutting down transport in 30 years, and they had more bombs and more people. These so-called security experts are just doing what the terrorists cannot - causing chaos.

And of course if I really wanted to take over a plane, I can still buy the perfect weapon after the security check, a bottle of duty-free whisky. A smashed glass bottle is at least as good a weapon at close quarters as a knife. But they won't stop selling that, it would cut into the airport's profits. The current delays add to airport profits, the longer the passengers are stuck in the departure lounge, the more they buy.