[1] http://site/
I write links in plain-text emails as: www.example.com/awesome-video-of-kittens.jsp?referrer=whatever
Note in particular that I don't put http in front, nor do I provide an alternative title.
Anyway it should still understand links without http because if I am typing the link out by hand (say because it is a site I remember) then I would still want it to be a link.
This is baffling for me. You are not new to the Internet, but until only quite recently, every single browser always showed the protocol is the address bar. Only of late did Google Chrome and then e.g. Mobile Safari remove “http://” from the display to save space; and yes, naturally they include this string when copy-pasting as doing otherwise would result in an incompletely pasted URI (protocols are not optional, except by current convention in non-hypertextual media).
And [title](http://url.goes.here) for in-line URLs.
One clear advantage of markdown is that its markup is designed to be as unobtrusive as possible to the point that its text/plain rendering is its own source. That's clearly not the case of MediaWiki or even Textile.
I'm not sure how you can say wiki markup is universally reviled without lumping markdown into that statement. You must have a particular flavor of wiki markup in mind.