I think that would be inconsistent. All existing @<whatever> fragments are evaluated at compile-time. Your @+, @|, @&, @^ feel more appropriate as proper functions (the compiler could still know of them, so it could optimize calls away)

Also: dictionary merge/intersect/difference aren't easily defined. For example, what should

  @&( @{ @"a":@"aye", @"b":@"bee" }, @{ @"a":@"ai ai", @"Bee":@"bee" })

return?