This sort of thing is a beautiful demonstration of marketing, big promises, and bombastic rhetoric in open source. But one of the best things about open source is that you don't have to take such claims at face value. If you actually look at the source, you'll find:
https://github.com/moot/riotjs/blob/29ae687ca0633b703e124331...
* A funny syntax for string interpolation. (Not templates)
* A strange bug relating to "popstate", ignoring browser support for folks on IE.
* A simple proxy to jQuery's `on`, `off`, `emit`, and `one` functions. (Why not just use jQuery events directly?)
* A simple proxy to "pushstate" and "popstate". (Ditto)
... and that's about it.
Calling this, "The fastest, smallest and most powerful client side framework for building large scale web applications," is pretty funny stuff — but I guess it might also be true. There's almost literally nothing here except for jQuery.
That said, if this were rewritten as a "you don't need a library to do MVC" blog post, then more power to it — it would be right on. But at the moment, it's a pretty spectacular piece of puffery — the sad thing being just how effective this sort of thing can be: http://cl.ly/SFzy. "Riot.js" might be a particularly egregious example, but similar tactics can be found all over the place. As a community, it would be nice if we could spend a little more time reading source, and seeing what libraries actually do and what can be done with them, and less time just drinking down the PR.
(And if this is all an elaborate joke, then I'm an ass for falling for it ;) But that's not the sense I get.)