Having just read the last few pages of this topic it seems that those who fly/teach in large jets,fly commercially and have the luxury of every concievable nav aid, IFR flight and radar for the whole journey are against the IMC rating, or that it should only be used with the protection of radar.
Those of us that fly in uncontrolled airspace in small 30yr old planes would do a lot less flying if every flight where conditions were a bit cloudy had to file a flight plan!
Are people suggesting that flying through a layer of cloud to get on top and enjoy a fabulous flight in sunshine above clouds should either be made illegal, or legal only if you had radar coverage?
As has been mentioned the quadrangle rule is there to give a degree of seperation in level flight in cloud.
Getting a RAS or RIS is not always practicable for short flights etc..
There is a risk in flying and I do not see any evidence that light aircraft are colliding in cloud.
I certainly do not agree with making it illegal, where would this attitude get us all in the end? Flight only when there is ten kilometers vis, no cross wind at departure/destination, no cloud anywhere, sun shining, no rain, drizzle or threat of it within 24hrs of the flight.........