A large part of jQuery's appeal is its modularity. The address-plugin already exists and seems to do the job very well.
In that spirit I'd prefer to see backbone stay as modular as possible, too, and have it integrate with existing, mature solutions, rather than grow its own knockou^Wknockoffs.
Modularity is great, but you don't need to worry about the way this is going. The entirety of Backbone.js is still fewer lines of code than just the jQuery Address plugin. ;)
Now that there is a bit more client-side-only code, in the next release, we'll probably split the source into individual components, so that you can just load Models and Collections on the server-side.
Yes, I didn't mean to dismiss backbone as a whole by any means. It's in fact on my "try asap" list (still undecided whether backbone or knockout is the way to go).
With modularity I don't strictly mean LOC. Rather I think that most of these lines in the address plugin are probably in there for a good reason. Thus if backbone ships its own solution to the problem, but that solution covers only part of what I need, then I'd have to integrate both - and perhaps deal with conflicts. That would be undesirable.
On the other hand I recognize that introducing dependencies to specific other plugins is also undesirable. I'm a bit torn about which is the lesser evil here.
A large part of jQuery's appeal is its modularity. The address-plugin already exists and seems to do the job very well.
In that spirit I'd prefer to see backbone stay as modular as possible, too, and have it integrate with existing, mature solutions, rather than grow its own knockou^Wknockoffs.