Features that we consider to be 'forward thinking', i.e. this is the future and you can't escape it.
Feature: IPv6 support
Status: 99% (complete, banning supported; needs large scale testing.)
This adds full support for IPv6 to Wedge. It's a new version of the IPv4 protocol designed to account for billions of IP addresses. Because SMF 2 only supports IPv4, it may encounter issues in the future with IP manipulation (logging, banning, etc.)
Target: modders, themers, users, geeks
Status: 100% (complete.)
You may also use jQuery inside your events. Also, Wedge allows you to add JS code simply by calling the add_js() function, and JS files with add_js_file(). Conversion of existing code in templates is made easier by the fact that commas are accepted within the add_js() calls, e.g. add_js('alert("', $txt['hello'], '");').
And because all code is postponed to the end of the page, you don't have to run anything in a DOMContentLoaded/DOMReady event, because the DOM is effectively built and ready to use by the time your code is run.
If you don't need jQuery or need your code to be executed before everything else, call add_js_inline(). The full DOM is still available at this point, but no jQuery, and no common Wedge functions. If you desperately want to run your code to be run in the middle of the DOM, don't bother with our functions and just use a script tag. We won't judge you.
Feature: CSS3 support
Target: themers, modders, users
Status: 100% (technically complete.)
With HTML5 always comes support for CSS3... Although it isn't a big deal in itself, it's likely to impact some of your users. SMF2's default theme fully supports IE6 (which was the dominant browser at the time of its first alpha versions.)
Wedge's simply doesn't. Welcome to 'progressive enhancement' (or 'graceful degradation', whatever crap professionals decide to call it.) Meaning it looks alright in IE6 (and somehow IE7 and IE8), and great in modern browsers. Wedge removes all of the SMF hacks and extra markup for IE6 ('topslice' and empty spans anyone?), although it's still possible to create themes that work perfectly in it. It's just a question of philosophy, I guess.
If you're afraid of losing your audience, don't forget the current penetration rates of IE6. The only country where it remains relatively popular is China. If most of your users are not Chinese, then don't bother with IE6 support, embrace full CSS3 support and actual good-looking themes. Oh yes, and support for IE4 and IE5 is entirely dropped, as their market shares are totally negligible. Last I heard, IE4 was now only used by a man called Gon Dongong, he's living in a Mormon community in Kazakhstan and even all of his friends laugh at him for being such a retard. I'm not judging, but I'll suggest that he keeps visiting SMF 1.0 forums. Or maybe YaBB.