I suggest to remove a feature from the D2 language, "Typesafe Variadic Functions" for class objects:
http://www.digitalmars.com/d/2.0/function.html

This is the example in the docs:


class Foo
{
    int x;
    char[] s;

    this(int x, char[] s)
    {
	this.x = x;
	this.s = s;
    }
}

void test(int x, Foo f ...);

...

Foo g = new Foo(3, "abc");
test(1, g);		// ok, since g is an instance of Foo
test(1, 4, "def");	// ok
test(1, 5);		// error, no matching constructor for Foo


In the last years I have never used this feature, so I think it's not useful often enough.

Once the feature is missing you have to replace code like this:
test(1, 4, "def");

With:
test(1, new Foo(4, "def"));

So it doesn't seem a significant loss.