I've been following the thread with not a little bemusement. I think that some people on the list are conflating optional with "will be everywhere!" Heck, I still look up the arguments for splice(). I fully expect to be looking up the various signature types for at least a year or two, and that's ok.
My criteria for good software:
Does it work?
Can someone else come in, make a change, and be reasonably certain no bugs were introduced?