I've been wondering about doing something like this before. Can we also use this change for Phobos?

AFAIK (didn't completely look into this yet), this will fail if T provides an "opCast":
http://d.puremagic.com/issues/show_bug.cgi?id=5747#c4

That said, if this is used only on "trivial internal types", this change should be fine (but documented as "incorrect"...)