Another language feature I want:
An 'in' keyword.
if (x in (1, 2, 4))
Seems pretty simple, and it'd be a boon for clarity, especially in cases like:
if (x == MyEnum.MyValue || x == MyEnum.MyOtherValue || x == MyEnum.MyOtherOtherValue)
Scoping the list would be interesting too:
if (x in MyEnum.(MyValue, MyOtherValue, MyOtherOtherValue))
is much easier to follow than the alternative.