The big new feature for weinre is the Timeline. The Chrome Dev Tools version of Timeline is documented here, and weinre implements some of it. A little of it. Timers, intervals, XHRs, some global events. It handles onerror, but I haven't seen onerror available on any mobile WebKit browsers, since it's a relatively new addition to WebKit.
Aside, if you're not familiar with WebKit Web Inspector / Chrome Dev Tools (same thing, different names), the Google Chrome Developer Tools site seems to be the best source of information.
What we really need is the real Web Inspector to work on mobile platforms. There's some code in WebKit to handle the remote-y-ness, as shown by this movie. Not shipping yet, though, AFAIK. Maybe on iOS 4.3 or already in Honeycomb but hidden? Would be a nice surprise for sure, but would make weinre - my baby - obsolete. That's fine with me, I've been developing software long enough I know that sometimes your creations need to die. There's plenty of other stuff to do in this arena.
What's next for weinre? You tell me. Or post a message on Twitter mentioning weinre, and I'll probably see it.
Here's the new movie for weinre: