What's wrong with std.variant.Variant?

[Andrei Alexandrescu]

I was curious about collecting a list of grievances about Variant. It's 
the oldest piece of generic code in std, and it predates a lot of good 
language additions.

So what's wrong with Variant? One thing I collected from a coworker is 
that it doesn't work with Windows DLLs, because in turn typeof() 
comparison does not work across Windows DLLs.

What are other problems with it?